Wafer pre-alignment method, wafer pre-alignment system and storage medium

Abstract

The present application relates to a wafer pre-alignment method. The method includes: using a displacement sensor to sample the circumference of the wafer to obtain displacement data of the circumference of the wafer; performing differential processing on the displacement data to obtain a differential result; determining the two end point positions of the notch or cut edge of the wafer and the center position of the notch or cut edge according to the differential result; determining the center offset of the wafer based on the displacement data; determining the deflection angle of the center of the notch or cut edge relative to the specified position according to the center position of the notch or cut edge and the center offset; adjusting the position of the wafer based on the deflection angle and the center offset. The above method only requires one data collection, combined with the differential result of the collected displacement data, to complete the wafer pre-alignment, which is time-consuming and computationally intensive.

Description

Technical Field

[0001] The present application relates to the field of manufacturing technology, and in particular to a wafer pre-alignment method, a wafer pre-alignment system, and a storage medium. Background Art

[0002] A wafer is a silicon wafer used to manufacture silicon semiconductor integrated circuits. The starting material is silicon. The main processing methods for wafers are sheet processing and batch processing, which involves processing one or more wafers simultaneously. In semiconductor manufacturing, some key equipment requires wafer pre-alignment.

[0003] In traditional related technologies, there are many methods for wafer pre-alignment, but most of them are relatively complicated and take a long time. Summary of the Invention

[0004] Based on this, it is necessary to provide a wafer pre-alignment method that is simple in calculation and short in time to address the above technical problems.

[0005] A wafer pre-alignment method, the method comprising:

[0006] Sampling the circumference of the wafer using a displacement sensor to obtain displacement data of the circumference of the wafer;

[0007] performing differential processing on the displacement data to obtain a differential result;

[0008] Determine two endpoint positions of the notch or cut edge of the wafer according to the differential result, and determine a center position of the notch or cut edge according to the two endpoint positions;

[0009] determining a center offset of the wafer based on the displacement data;

[0010] Determining a deflection angle of the center of the notch or the cut edge relative to a specified position according to the center position of the notch or the cut edge and the circle center offset;

[0011] The position of the wafer is adjusted based on the deflection angle and the center offset.

[0012] In one embodiment, searching for two maximum difference results in the difference results includes:

[0013] Finding the maximum value in the difference results;

[0014] Filtering a preset number of differential results on both sides of a position corresponding to a maximum value in the differential result, and filtering out the maximum value to obtain a filtered differential result;

[0015] Finding the maximum value in the filtered difference result;

[0016] Calculating the difference between the maximum value in the differential result and the maximum value in the filtered differential result;

[0017] When the difference is between a first preset threshold and a second preset threshold, the maximum value in the differential result and the maximum value in the filtered differential result are determined as two maximum differential results in the differential result; wherein the first preset threshold is less than the second preset threshold.

[0018] In another embodiment, after calculating the difference between the maximum value in the differential result and the maximum value in the filtered differential result, when the difference is outside the first preset threshold and the second preset threshold, a new starting point is selected, starting from the new starting point, and returning to the step of sampling the circumference of the wafer using the displacement sensor to obtain the displacement data of the circumference of the wafer.

[0019] In one embodiment, determining the center position of the notch or the cut edge according to the positions of the two endpoints includes:

[0020] Read the index values corresponding to the two maximum value difference results respectively;

[0021] Calculate the average of the two index values and round them up to obtain a middle index value;

[0022] The position corresponding to the middle index value is determined as the center position of the notch or the cut edge.

[0023] In one embodiment, determining the center position of the notch or the cut edge according to the positions of the two endpoints includes:

[0024] Finding the minimum difference result among the difference results between the positions corresponding to the two maximum difference results;

[0025] The position corresponding to the minimum difference result is determined as the center position of the notch or the cut edge.

[0026] In one embodiment, determining the deflection angle of the center of the notch or the cut edge relative to the specified position based on the center position of the notch or the cut edge and the center offset includes:

[0027] Obtaining the actual position of the center of the wafer according to the center offset;

[0028] According to the actual position of the circle center, the center position of the turntable and the center position of the notch or the cut edge, a deflection angle of the center of the notch or the cut edge compared to the specified position is determined in combination with trigonometric functions.

[0029] In one embodiment, determining the center offset of the wafer based on the displacement data includes:

[0030] Respectively removing a preset number of displacement data on both sides of the two end points of the notch or cut edge and non-uniform displacement data from the displacement data;

[0031] A preset number of symmetrical data groups are selected from the displacement data after elimination, and the center offset of the wafer is determined based on the selected data groups.

[0032] A wafer pre-alignment system includes: a displacement sensor, a programmable logic controller (PLC), a stepper driver, a stepper motor, and a turntable; the stepper driver receives a control signal from the PLC and drives the stepper motor based on the control signal; a wafer is placed on the turntable, which is rotated by the stepper motor; and the stepper motor controls the turntable to rotate the wafer.

[0033] The programmable logic controller obtains displacement data obtained by the displacement sensor sampling the circumference of the wafer; differentiates the displacement data to obtain a differential result; determines the two end point positions of the notch or cut edge of the wafer based on the differential result, and determines the center position of the notch or cut edge based on the differential result; determines the center offset of the wafer based on the displacement data; determines the deflection angle of the center of the notch or cut edge compared to the specified position based on the center position of the notch or cut edge and the center offset; and adjusts the position of the wafer based on the deflection angle and the center offset.

[0034] A computer-readable storage medium stores a computer program, which performs the steps in the wafer pre-alignment method when executed by a processor.

[0035] The above-mentioned wafer pre-alignment method, wafer pre-alignment system and storage medium obtain displacement data by collecting the circumference of the wafer, and perform differential calculation on the displacement data to obtain a differential result. The two endpoint positions and the center position of the missing area of the wafer are determined based on the differential result. At the same time, the center offset of the wafer is determined based on the displacement data. The deflection angle of the center of the notch or cut edge relative to the specified position is determined based on the center point position and the center offset. Finally, the position of the wafer is adjusted based on the center offset and the deflection angle to complete the wafer pre-alignment positioning. The above-mentioned method only requires one data collection, combined with the differential result of the collected displacement data, to complete the wafer pre-alignment, which is time-saving and computationally intensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a structural block diagram of a wafer pre-alignment system in one embodiment;

[0037] Figure 21 is a schematic flow chart of a wafer pre-alignment method according to an embodiment;

[0038] Figure 3 (1) is a schematic diagram of a wafer with a notch in a specific embodiment;

[0039] Figure 3(2) is a schematic diagram of a wafer with cut edges in a specific embodiment;

[0040] Figure 4 A schematic diagram of a process for determining two end points of a notch or a cut edge of a wafer based on a differential result and a center position of the notch or the cut edge of the wafer based on the differential result in one embodiment;

[0041] Figure 5 In another embodiment, the two end points of the notch or cut edge of the wafer are determined according to the differential result, and the center position of the notch or cut edge of the wafer is determined according to the differential result.

[0042] Figure 6 A schematic diagram of a process for searching two maximum difference results in a difference result in one embodiment;

[0043] Figure 7 A schematic diagram of the positions of various points when determining the deflection angle required for a notch or a trimming edge in one embodiment;

[0044] Figure 8 A schematic diagram of a wafer pre-alignment system executing a wafer pre-alignment method in one embodiment. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0046] The wafer pre-alignment method provided in this application can be applied to Figure 1 The wafer pre-alignment system shown in FIG. The wafer pre-alignment system includes a displacement sensor 1, a programmable logic controller (not shown), a stepper driver (not shown), a stepper motor 2, and a turntable 3. The stepper driver receives control signals from the programmable logic controller and drives the stepper motor 2 based on the control signals. The wafer is placed on the turntable 3, which is controlled by the stepper motor 2 and rotates with the turntable 3.

[0047] The programmable logic controller obtains displacement data obtained by the displacement sensor 1 when sampling the circumference of the wafer; performs differentiation on the displacement data to obtain a differential result; determines the two end point positions of the notch or cut edge of the wafer and the center position of the notch or cut edge based on the differential result; determines the center offset of the wafer based on the displacement data; determines the deflection angle of the center of the notch or cut edge compared to the specified position based on the center position and the center offset; and adjusts the position of the wafer based on the deflection angle and the center offset.

[0048] In one embodiment, Figure 2 As shown, a wafer pre-alignment method is provided, which is applied to Figure 1 The programmable logic controller in FIG. 1 is used as an example to illustrate the method, which includes steps S210 to S260.

[0049] In step S210 , a displacement sensor is used to sample the circumference of the wafer to obtain displacement data of the circumference of the wafer.

[0050] In one embodiment, a wafer is placed on a turntable. A displacement sensor located at a fixed position collects edge data of the wafer as the turntable rotates one revolution. This data is then collected along the wafer's circumference. The corresponding motor angle is also recorded for each displacement data point. In one embodiment, a high-precision displacement sensor is used to collect data along the wafer's circumference.

[0051] Step S220: performing differential processing on the displacement data to obtain a differential result.

[0052] In one embodiment, performing differential processing on the displacement data includes performing first-order differential processing on the displacement data. In this embodiment, the result obtained by the differential processing is recorded as a differential result.

[0053] Step S230 , determining two end point positions of the notch or cut edge of the wafer according to the differential result, and determining a center position of the notch or cut edge according to the two end point positions.

[0054] In one embodiment, FIG3(1) is a schematic diagram of a wafer with a notch in a specific embodiment, and FIG3(2) is a schematic diagram of a wafer with a cut edge in a specific embodiment. The endpoints of the notch or cut edge refer to the positions of the two ends of the notch or cut edge as shown in FIG3(1) and FIG3(2) at positions 301 to 304, and the center position of the notch or cut edge is shown in FIG3(1) and FIG3(2) at positions 305 and 306.

[0055] Step S240 , determining the center offset of the wafer based on the displacement data.

[0056] The center offset refers to the offset of the center position of the wafer relative to the center position of the turntable.

[0057] In one embodiment, the center offset of the wafer is determined based on the displacement data, including: removing a preset number of displacement data on both sides of the two end points of the notch or cut edge, as well as non-uniform displacement data in the displacement data; selecting a preset number of symmetrical data groups from the removed displacement data, and determining the center offset of the wafer based on the selected data groups.

[0058] In one embodiment, determining the center offset of the wafer based on the selected data set includes: performing circle center fitting using a gyration radius method based on the selected data set, and then determining the center offset of the wafer.

[0059] Step S250 : determining a deflection angle of the center of the notch or the cut edge relative to the designated position according to the center position of the notch or the cut edge and the center offset.

[0060] The deflection angle refers to the angle required to rotate the center of the notch or trim to a specified position. The specified position is the target position of the center of the notch or trim. During wafer pre-alignment, the center of the notch or trim must be adjusted to the specified position. In one embodiment, after determining the center position of the notch or trim, the motor angle corresponding to the center position can be obtained.

[0061] Step S260 , adjusting the position of the wafer based on the deflection angle of the notch or the cut edge and the center offset.

[0062] After determining the center deflection angle and center point position of the missing area, the wafer can be positioned according to the deflection angle and center offset of the notch or cut edge, so that the wafer finally stays at a position that meets the conditions, completing wafer pre-alignment.

[0063] The above-mentioned wafer pre-alignment method obtains displacement data by sampling the circumference of the wafer, and performs differential calculation on the displacement data to obtain a differential result. The two endpoint positions and the center position of the wafer notch or cut edge are determined based on the differential result. At the same time, the center offset of the wafer is determined based on the displacement data. The deflection angle of the center of the notch or cut edge relative to the specified position is determined based on the center position and the center offset. Finally, the position of the wafer is adjusted based on the deflection angle of the notch or cut edge and the center offset to complete the wafer pre-alignment. The above-mentioned method only requires one data collection, combined with the differential result of the collected displacement data, to complete the wafer pre-alignment, which is time-saving and computationally intensive.

[0064] In one embodiment, Figure 4 As shown, the two end point positions of the notch or cut edge of the wafer are determined according to the differential result, including step S410 and step S420.

[0065] Step S410: searching for two maximum difference results in the difference results.

[0066] In this embodiment, two maximum values need to be found from the difference results.

[0067] In step S420 , the positions corresponding to the two maximum value difference results are determined as the two end points of the notch or the cut edge of the wafer.

[0068] According to the characteristics of the wafer edge change rate, the two places where the edge change rate of the notch or cut edge is the largest are the two ends of the notch or cut edge. Therefore, in this embodiment, the positions corresponding to the two maximum value difference results found in the difference result are determined as the two endpoint positions.

[0069] Further, in one embodiment, please continue to refer to Figure 4 Determining the center position of the notch or cut edge of the wafer according to the differential result includes steps S430 to S450.

[0070] Step S430, respectively read the index values of the two maximum value difference results.

[0071] Step S440: Calculate the average of the two index values and round them up to obtain a middle index value.

[0072] Step S450: determining the position corresponding to the middle index value as the center position of the notch or the cut edge.

[0073] In this embodiment, the displacement data collected based on the two end point positions of the notch or cut edge has the property of a large rate of change. Two maximum differential results are found from the differential results to determine as the two end point positions of the notch or cut edge of the wafer, and then the index values of the two end point positions (two maximum differential results) are read. The center is determined by averaging the two read index values and rounding them up, which is determined as the center position of the notch or cut edge. The calculation is simple, time-saving, and can improve the efficiency of wafer pre-alignment.

[0074] In another embodiment, Figure 5 As shown, determining the center position of the notch or the trimming according to the difference result includes step S510 and step S520.

[0075] Step S510: Find the minimum difference result among the difference results between the positions corresponding to the two maximum difference results. Step S520: Determine the position corresponding to the minimum difference result as the center position of the notch or the trimming edge.

[0076] In this embodiment, the displacement data collected based on the two endpoint positions of the notch or cut edge has the property of a large rate of change, and two maximum differential results are found from the differential results to be determined as the two endpoint positions of the notch or cut edge of the wafer, and then by finding the minimum value in the differential results between the two endpoint positions (two maximum differential results), the position corresponding to the minimum value is determined as the center position of the notch or cut edge; the calculation is simple, time-saving, and can improve the efficiency of wafer pre-alignment.

[0077] In one embodiment, searching for two maximum value difference results in the difference results includes: obtaining two maximum value difference results by taking two difference results with the largest difference result values.

[0078] In one embodiment, Figure 6 As shown, searching for two maximum value difference results in the difference results includes steps S610 to S640.

[0079] Step S610 , filtering a preset number of differential results on both sides of a position corresponding to the maximum value in the differential result, and filtering out the maximum value to obtain a filtered differential result.

[0080] Step S620: Find the maximum value in the filtered difference result.

[0081] After finding the maximum value in the differential results, a preset number of differential results on both sides of the position corresponding to the maximum value are filtered, and then the maximum value is found in the filtered differential results to obtain the two maximum values in all the differential results. The preset number can be set according to actual conditions.

[0082] Step S630 , respectively reading the index value of the maximum value in the differential result and the index value corresponding to the maximum value in the filtered differential result, and calculating the difference between the two index values.

[0083] Step S640: When the difference value is between the first preset threshold value and the second preset threshold value, the maximum value in the differential result and the maximum value in the filtered differential result are determined as two maximum value differential results in the differential result.

[0084] If the starting point of displacement data acquisition is located at a gap or cut edge, analyzing the differential results can be complex. Therefore, in this embodiment, after finding two maxima in the differential results, the interval between the two maxima is determined. If the difference between the maximum indexes is between a first preset threshold and a second preset threshold, the starting point of the displacement data acquisition is considered not to be located at a gap or cut edge. In this case, the two maxima are determined as the two maximum differential results in the differential results. The first and second preset thresholds are two non-equal positive real numbers, and their specific values can be set based on actual conditions.

[0085] In another embodiment, please refer to Figure 6 The above method also includes step S650, when the calculated difference between the two index values is outside the first preset threshold and the second preset threshold (taking the first preset threshold as an example, that is, the difference is less than or equal to the first preset threshold or greater than or equal to the second preset threshold), selecting a new starting point, starting from the new starting point, and returning to the step of using the displacement sensor to sample the circumference of the wafer to obtain the displacement data of the circumference of the wafer.

[0086] In one embodiment, if the calculated difference is outside the first preset threshold and the second preset threshold, the wafer is first rotated to a specified angle and then new data is collected again.

[0087] In the above embodiment, the two maximum values in the differential result are found by searching for the maximum value in the differential result twice, and the difference between the two maximum value indexes found is compared with the preset threshold. If the difference between the two maximum value indexes is between the preset threshold, it is determined as the two maximum value differential results in the differential result. This can avoid misjudgment and improve the accuracy of wafer pre-alignment.

[0088] In one embodiment, the center deflection angle of the notch or cut edge is determined based on the center position of the notch or cut edge and the center offset, including: obtaining the actual center position of the wafer based on the center offset; determining the deflection angle of the notch or cut edge based on the actual center position, the center position when collecting displacement data, and the center position of the notch or cut edge in combination with trigonometric functions.

[0089] In a specific embodiment, Figure 7 As shown, an XOY rectangular coordinate system is established with the turntable center O as the origin. Taking the wafer center O' in the first quadrant of the XOY coordinate system as an example, point A shown in the figure represents the center position of the notch or cut edge. The wafer pre-alignment process requires the wafer center to be rotated to coincide with the turntable center, and point A to be rotated to 0 degrees at the same time.

[0090] The distance between the turntable center and the displacement sensor is L, and the offset from A to the displacement sensor is S, then OA = L + S. In the XY coordinate system, let the angle between the X axis (0 degrees) and the displacement sensor be Θ, and the angle from A to the displacement sensor be α (after determining the position of point A, the angle corresponding to point A can be determined). ∠BOO' and ∠BO'O can be calculated using trigonometric functions from the offsets in step 2. Therefore, ∠XOA = Θ - α, and ∠AOO' = ∠XOA - ∠BOO'. In triangle AOO', the law of cosines allows us to derive the length R of AO', and further calculate the angle of AO'O: ∠AO'X' = 270 - ∠AO'O - ∠BO'O, where ∠AO'X' is β. After translating the wafer in the negative Y' direction, O' coincides with B, and X' coincides with X. After rotating the turntable 90 degrees counterclockwise, the X'-axis and Y-axis coincide, and the Y'-axis and X-axis coincide, but in opposite directions. The wafer center and the turntable center are now aligned. The angle A needs to rotate to 0 degrees is δ = 270 - β, which is the center deflection angle of the notch or trim.

[0091] In the above embodiment, after determining the actual position of the circle center, the center position of the turntable, and the center position of the notch or cut edge, the center deflection angle of the notch or cut edge relative to the specified position can be determined based on these positions and combined with appropriate trigonometric functions. The calculation method is simple and time-saving.

[0092] In a specific embodiment, Figure 8 FIG. 1 is a schematic diagram showing a wafer pre-alignment method executed by a wafer pre-alignment system in this embodiment. The wafer pre-alignment method includes the following steps:

[0093] 1. First, start the motor and rotate it at a constant speed for one circle. At the same time, use the displacement sensor to sample the circumference of the wafer. After data collection is completed, perform a first-order difference on the collected displacement data, and then find the maximum value of the first-order difference (based on the characteristics of the wafer change rate, the two places where the change rate of the notch or trim edge is the largest are the two ends of the notch or trim edge) to determine the two endpoints of the wafer notch or trim edge. Finally, by finding the average of the two maximum value indexes or the index of the minimum value of the data between the two maximum values, the center of the wafer notch or trim edge is determined, and then the angle at which the center of the notch or trim edge is located is determined.

[0094] 2. After finding the notch or cut edge of the wafer, since the collected data will be asymmetric during the acceleration and deceleration of the motor, it is necessary to eliminate the first preset number of displacement data during the acceleration and deceleration of the motor and around the notch or cut edge from the collected data, and then select the second preset number of groups of displacement data with symmetrical angles from the remaining data, and use the gyration radius method to determine the offset of the wafer center.

[0095] 3. Establish a new rectangular coordinate system with the actual position of the wafer center as the origin, and calculate the final deflection angle using trigonometric functions.

[0096] 4. Adjust the position of the wafer based on the deflection angle of the notch or cut edge and the center offset to complete the positioning.

[0097] In the above wafer pre-alignment method, only one sampling is required to determine the deflection angle of the notch or trimmed edge and the center offset of the wafer, which is time-saving and computationally intensive. Furthermore, in another embodiment, if further accuracy is required, a second sampling can be performed after the notch or trimmed edge is located before positioning.

[0098] It should be understood that although Figure 2-7 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 2-7 At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The order of execution of these steps or stages is not necessarily one by one, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0099] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0100] A displacement sensor is used to sample the circumference of the wafer to obtain displacement data of the circumference of the wafer; the displacement data is differentially processed to obtain a differential result; the two end point positions of the missing area of the wafer and the center point position of the missing area are determined based on the differential result; the center offset of the wafer is determined based on the displacement data; the center deflection angle of the missing area is determined based on the center point position and the center offset of the missing area; and the position of the wafer is adjusted based on the center deflection angle and the center point position.

[0101] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: searching for two maximum differential results in the differential results; and determining positions corresponding to the two maximum differential results as two end point positions of the missing area of the wafer.

[0102] In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: reading the index values of the two maximum difference results respectively; calculating the average of the two index values and rounding them to obtain an intermediate index value; and determining the position corresponding to the intermediate index value as the center point position of the missing area.

[0103] In another embodiment, when the computer program is executed by the processor, the following steps are further implemented: finding the minimum difference result among the difference results between the positions corresponding to the two maximum difference results; and determining the position corresponding to the minimum difference result as the center point position of the missing area.

[0104] In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: finding the maximum value in the differential result, replacing a preset number of differential results on both sides of the position corresponding to the maximum value in the differential result with 0, and obtaining the replaced differential result; finding the maximum value in the replaced differential result; calculating the difference between the maximum value in the differential result and the maximum value in the replaced differential result; when the difference is greater than a preset threshold, determining the maximum value in the differential result and the maximum value in the replaced differential result as two maximum differential results in the differential result.

[0105] In another embodiment, when the computer program is executed by the processor, the following steps are also implemented: after calculating the difference between the maximum value in the differential result and the maximum value in the differential result after replacement, when the difference is less than or equal to a preset threshold, a new starting point is selected, starting from the new starting point, and returning to the step of sampling the circumference of the wafer using the displacement sensor to obtain the displacement data of the circumference of the wafer.

[0106] In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: obtaining the actual position of the center of the wafer based on the center offset; determining the center deflection angle of the missing area based on the actual position of the center, the center position when the displacement data is collected, and the center point position of the missing area in combination with trigonometric functions.

[0107] In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: a preset number of displacement data on both sides of the two endpoint positions of the missing area in the displacement data are eliminated; a preset number of symmetrical data groups are selected from the eliminated displacement data, and the center offset of the wafer is determined based on the selected data groups.

[0108] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A wafer pre-alignment method, characterized in that: The method comprises: Sampling the circumference of the wafer using a displacement sensor to obtain displacement data of the circumference of the wafer; performing differential processing on the displacement data to obtain a differential result; Determine two endpoint positions of the notch or cut edge of the wafer according to the differential result, and determine a center position of the notch or cut edge according to the two endpoint positions; Respectively removing a preset number of displacement data on both sides of the two end points of the notch or cut edge and non-uniform displacement data from the displacement data; Selecting a preset number of symmetrical data groups from the displacement data after elimination, and performing circle center fitting using a gyration radius method based on the selected data groups to determine the center offset of the wafer; Determining a deflection angle of the center of the notch or the cut edge relative to a specified position according to the center position of the notch or the cut edge and the circle center offset; The position of the wafer is adjusted based on the deflection angle and the center offset.

2. The method according to claim 1, characterized in that Determining the two endpoint positions of the notch or cut edge of the wafer according to the differential result includes: Finding two maximum difference results in the difference results; The positions corresponding to the two maximum value difference results are determined as the two end point positions of the notch or the cut edge of the wafer.

3. The method according to claim 2, characterized in that The step of searching for two maximum value difference results in the difference results includes: Finding the maximum value in the difference results; Filtering a preset number of differential results on both sides of a position corresponding to a maximum value in the differential result, and filtering out the maximum value to obtain a filtered differential result; Finding the maximum value in the filtered difference result; Respectively reading the index value of the maximum value in the differential result and the index value corresponding to the maximum value in the filtered differential result, and calculating the difference between the two index values; When the difference value is between a first preset threshold value and a second preset threshold value, the maximum value in the differential result and the maximum value in the filtered differential result are determined as two maximum value differential results in the differential result.

4. The method according to claim 3, characterized in that After respectively reading the index value of the maximum value in the differential result and the index value corresponding to the maximum value in the filtered differential result, and calculating the difference between the two index values, when the difference is outside the first preset threshold and the second preset threshold, selecting a new starting point, starting from the new starting point, and returning to the step of sampling the circumference of the wafer using the displacement sensor to obtain the displacement data of the circumference of the wafer.

5. The method according to claim 2, characterized in that Determining the center position of the notch or the cut edge according to the two endpoint positions includes: Read the index values corresponding to the two maximum value difference results respectively; Calculate the average of the two index values and round them up to obtain a middle index value; The position corresponding to the middle index value is determined as the center position of the notch or the cut edge.

6. The method according to claim 2, characterized in that Determining the center position of the notch or the cut edge according to the two endpoint positions includes: Finding the minimum difference result among the difference results between the positions corresponding to the two maximum difference results; The position corresponding to the minimum difference result is determined as the center position of the notch or the cut edge.

7. The method according to claim 1, characterized in that The determining, based on the center position of the notch or the cut edge and the circle center offset, of a deflection angle of the center of the notch or the cut edge relative to a specified position includes: Obtaining the actual position of the center of the wafer according to the center offset; According to the actual position of the circle center, the center position of the turntable and the center position of the notch or the cut edge, a deflection angle of the center of the notch or the cut edge compared to the specified position is determined in combination with trigonometric functions.

8. A wafer pre-alignment system, characterized in that: The system includes: a displacement sensor, a programmable logic controller, a stepper driver, a stepper motor, and a turntable; the stepper driver receives a control signal from the programmable logic controller and drives the stepper motor based on the control signal; a wafer is placed on the turntable, which is controlled by the stepper motor; and the stepper motor controls the turntable to drive the wafer to rotate; The programmable logic controller obtains displacement data obtained by the displacement sensor sampling the circumference of the wafer; differentiates the displacement data to obtain a differential result; determines the two end point positions of the notch or cut edge of the wafer according to the differential result, and determines the center position of the notch or cut edge according to the differential result; removes a preset number of displacement data on both sides of the two end point positions of the notch or cut edge and non-uniform displacement data from the displacement data; selects a preset number of symmetrical data groups from the removed displacement data, and based on the selected data groups, uses the gyration radius method to perform circle center fitting to determine the center offset of the wafer; determines the deflection angle of the center of the notch or cut edge compared to the specified position according to the center position of the notch or cut edge and the circle center offset; and adjusts the position of the wafer based on the deflection angle and the circle center offset.

9. The system according to claim 8, characterized in that The programmable logic controller further searches for two maximum value differential results in the differential results; and determines positions corresponding to the two maximum value differential results as two end point positions of the notch or cut edge of the wafer.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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