Method for positioning and processing through holes in wafer electroplating shielding plate and shielding plate

Abstract

The invention discloses a method for positioning and processing through holes in a wafer electroplating shield plate and the shield plate, the method is used for positioning and processing a plurality of circles of through holes sequentially distributed from inside to outside in the shield plate, the circles of through holes are distributed around the center of the shield plate in a circumferential array manner, the chord lengths among the circles of holes are gradually increased from inside to outside, and the chord lengths are equal in step length. The method comprises the following steps: S1, establishing a coordinate system; s2, calculating the coordinate position of each hole; and S3, processing. On one hand, the coordinate system is established on the shielding plate based on the layout of the chips on the wafer, the initial calculation parameters are adjusted based on the coordinate positions of the through holes and analogue simulation, finally, the distribution of the through holes is controlled to be correspondingly matched with the distribution of the wafer chips, and the coating quality of the chip area is effectively improved; on the other hand, based on the angular deviation formed by the through holes in the adjacent ring layers, stress concentration in machining is effectively avoided, and the product yield is increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor processing, and in particular relates to a through-hole positioning and processing method on a wafer electroplating shielding plate, and also relates to a shielding plate. Background Art

[0002] Wafer electroplating is often performed using a constant current mode. While this constant current deposition setup ensures a constant total current, it doesn't guarantee a uniform current density distribution. Due to the wafer's resistance, the current tends to concentrate at the edges (near the contact point), where the resistance is lower, resulting in lower current density in the center. This uneven distribution can cause the deposition rate to be faster at the edges than in the center.

[0003] Currently, to improve the quality of wafer surface coatings, a shielding plate with multiple holes is typically designed and installed on one side of the wafer during electroplating to adjust the current density across the wafer and, in turn, improve the uniformity of the coating. This is achieved by adjusting the hole density and current density by varying the aperture diameter or spacing of the through-holes in the center and edge areas of the shielding plate. Therefore, during processing, the holes in each layer are typically processed from the inside out or from the outside in, with a single point on the shielding plate (usually the center of the plate) serving as the reference center. The layout of the holes typically includes circular, honeycomb (hexagonal), and square shapes.

[0004] However, in the actual processing process, since the shielding plate is mainly a rectangular or circular symmetrical structure, the initial position of the holes on the shielding plate is random, making it difficult to ensure that the distribution of the holes finally formed on the shielding plate corresponds to the distribution position of the chips on the wafer. During the electroplating process, it is easy to affect the uniformity of the plating thickness in the area where the chips are distributed on the wafer; in addition, since there are many holes on the shielding plate and their distribution is dense, stress concentration is easy to occur during processing, resulting in deformation or damage to the plate. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a new method for positioning and processing through holes on a wafer electroplating shielding plate.

[0006] At the same time, the present invention also provides a shielding plate.

[0007] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A method for positioning and processing through holes on a wafer electroplated shielding plate is provided. The method is used to position and process multiple circles of through holes distributed sequentially from the inside outward on the shielding plate. Each circle of through holes is arranged in an array around the central circumference of the shielding plate. The chord length between adjacent holes in each circle increases stepwise from the inside out, and the chord length steps are equal. The method comprises the following steps:

[0009] S1. Establish a coordinate system

[0010] Taking the chip on the wafer as the reference, establish a rectangular coordinate system with the center of the shielding plate as the origin. During alignment, the orthographic projection of the chip on the wafer on the shielding plate is symmetrically distributed in the four quadrants of the coordinate system about the X and Y axes.

[0011] S2. Calculate the coordinate position of each hole

[0012] 1) Based on the wafer size, set the maximum opening radius, chord length step, and maximum chord length of the shielding plate;

[0013] 2) Based on the maximum opening radius, chord length step, and maximum chord length, mathematical models are established for the distance between the center of each circle of through holes and the origin of the coordinate system, as well as the offset angle of each circle of through holes relative to the X-axis or Y-axis. The through holes of each circle are symmetrically distributed in the four quadrants of the coordinate system about the X and Y axes, and the offset angles of corresponding through holes in each adjacent circle are maintained to form a deviation.

[0014] 3) establishing a coordinate position mathematical model of each through hole based on the obtained offset angle and radial distance of each through hole;

[0015] 4) Based on the obtained coordinate positions of each through hole and the simulated coating distribution, adjust the maximum opening radius or chord length step or maximum chord length in step 1), and repeat steps 2) and 3) until the simulated coating distribution uniformity is optimal and determine the coordinate positions of each through hole based on the result;

[0016] S3, Processing

[0017] Based on the coordinate position of each through hole obtained in step S2, the tool is controlled to process the through holes circle by circle.

[0018] Preferably, in the distance mathematical model, the number of through-hole circles and the radial distance between adjacent circles are first calculated, where each circle is numbered 1, 2, 3... from the inside to the outside; then, based on the number value of each circle and the radial distance between adjacent circles, the distance from the center of each through-hole circle to the origin of the coordinate system is calculated.

[0019] Preferably, the number of through-hole turns is calculated based on the maximum chord length, and then the actual number of through-hole turns is taken as the largest integer less than this value, and the actual radial distance between adjacent turns is calculated based on this largest integer. In this way, the maximum turn value is precisely controlled.

[0020] Preferably, in the mathematical model of the offset angle, the chord length between the through holes of each layer is first calculated; then, based on the number value of each layer, the actual radial distance and the chord length of each layer, the number of through holes in each layer and the arc between adjacent through holes are calculated; finally, the through holes in each layer are numbered 1, 2, 3... in sequence, and based on the number value and the arc between each through hole, the offset angle of each through hole is calculated in sequence.

[0021] Specifically, when calculating the number of through-holes in each circle layer, the shielding plate is divided into multiple areas with the center of the shielding plate as the center of the circle, and the number of through-holes in each circle layer in any area is calculated and an integer value is taken, and the number of through-holes in each circle layer is calculated based on the integer value and the number of areas. Usually, the shielding plate is divided into four areas, and the integer number of through-holes in each circle layer in a single area is calculated (the purpose is to eliminate the non-integer value problem that may occur when directly calculating the number of through-holes in the entire circle layer), and then the number of through-holes is multiplied by the number of areas to obtain the accurate number of through-holes in each circle layer. Here, compared to directly calculating the number of through-holes in the entire circle layer and rounding it off, the calculation method of the present application is used, and the obtained number of through-holes is more accurate and has a smaller deviation.

[0022] Preferably, the multiple circle through holes are divided into multiple first circle groups and multiple second circle groups, wherein the multiple first circle groups and the multiple second circle groups are staggered in the radial direction of the shielding plate; processing polarities corresponding to the first circle groups and the second circle groups are set, and the offset angle is calculated based on the processing polarities, and the calculation formula is as follows:

[0023] θ=(N-1)*H+S*H / m;

[0024] Where θ is the offset angle of the through-hole, N is the through-hole number, H is the arc between holes, S is the machining polarity, and m is an even number greater than 1. By grouping through-holes and introducing machining polarity, the angular offset must be strictly maintained when arranging multiple circles of holes.

[0025] Specifically, when calculating the through-hole offset angle for the first circle group, S = 1, and when calculating the through-hole offset angle for the second circle group, S = 0; and / or m = 2. By limiting the value of m, the initial position through-holes of the corresponding circle layer are ensured to be symmetrical with the adjacent through-holes about the corresponding polar axis of the coordinate system. This allows positioning and machining of the remaining through-holes, starting with the initial position through-holes, to be performed continuously, with minimal deviation and high precision.

[0026] Preferably, in step S3, the coordinate system is used as a reference to determine the original angle of the tool starting point relative to the X or Y axis, and the through holes are processed sequentially based on the original angle and the offset angle of each through hole. This facilitates the tool to perform processing accurately.

[0027] Another technical solution of the present invention is a shielding plate for wafer electroplating, which is made by the above-mentioned positioning and processing method to form multiple circles of through holes distributed in sequence from the inside to the outside and with consistent apertures, wherein each circle of through holes is distributed in an array around the central circumference of the shielding plate and matches the chip on the wafer, and the chord length between the holes of each circle increases step by step from the inside to the outside, and the chord length step length is equal.

[0028] In addition, the apertures of the through holes on the shielding plate are equal. Here, the layout of the through holes with the same aperture can adjust the current density while facilitating processing.

[0029] Due to the implementation of the above technical solution, the present invention has the following advantages compared with the prior art:

[0030] In the prior art, since the shielding plate is mainly a rectangular or circular symmetrical structure, the initial processing position of the holes on the shielding plate is random, making it difficult to ensure that the distribution of the holes finally formed on the shielding plate corresponds to the distribution position of the chips on the wafer. During the electroplating process, it is easy to affect the uniformity of the plating thickness in the area where the chips are distributed on the wafer; in addition, since there are many holes on the shielding plate and they are densely distributed, stress concentration is easy to occur during processing, resulting in deformation or damage to the plate; and the present application comprehensively designs the through-hole positioning and processing method on the wafer electroplating shielding plate, cleverly solving the deficiencies and defects of the prior art. After adopting the positioning and processing method, first, the chip on the wafer is used as a reference, and a rectangular coordinate system with the center of the shielding plate as the origin is established. During alignment, the positive projection of the chip on the wafer on the shielding plate is symmetrically distributed in the four quadrants of the coordinate system about the X and Y axes; then, based on the wafer The circle size is set, and the maximum opening radius, chord length step, and maximum chord length of the shielding plate are set; then, according to the maximum opening radius, chord length step, and maximum chord length, a mathematical model of the distance between the center of each circle of through holes and the origin of the coordinate system and a mathematical model of the offset angle of each circle of through holes relative to the X-axis or Y-axis are established in sequence, wherein the through holes of each circle are kept symmetrically distributed in the four quadrants of the coordinate system about the X and Y axes, and the offset angles of the corresponding through holes of each adjacent circle are kept to form a deviation. Based on the offset angles and radial distances of each through hole obtained, a mathematical model of the coordinate position of each through hole is established; in combination with the obtained coordinate positions of each through hole and the simulation, the maximum opening radius or chord length step or maximum chord length is adjusted, and the above steps are repeated until the simulated coating distribution uniformity is optimal and the coordinate positions of each through hole under the result are determined; finally, based on the obtained coordinate positions of each through hole, the tool is controlled to process the through hole circle by circle. Therefore, compared with the existing technology, the present invention, on the one hand, establishes a coordinate system on the shielding plate based on the chip layout on the wafer, and adjusts the initial calculation parameters based on the coordinate position of each through hole and simulation simulation, and finally controls the through hole distribution to correspond to the wafer chip distribution, effectively improving the chip area plating quality; on the other hand, based on the angle deviation formed by the through holes of adjacent circles, it effectively avoids stress concentration during processing and improves product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic front view of the shielding plate of the present invention;

[0032] Figure 2 It is a schematic diagram of the front view of the wafer of the present invention; DETAILED DESCRIPTION

[0033] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0034] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0036] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0037] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0038] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0039] like Figure 1 and Figure 2 As shown, the present embodiment involves a method for positioning and processing through holes on a wafer electroplating shielding plate, which is used for positioning and processing multiple circles of through holes distributed sequentially from the inside to the outside on the shielding plate. The through holes in each circle are distributed in an array around the central circumference of the shielding plate. The chord length between adjacent holes in each circle increases step by step from the inside to the outside, and the chord length step length is equal. The method includes the following steps: S1, establishing a coordinate system; S2, calculating the coordinate position of each hole; S3, processing.

[0040] Specifically, this embodiment takes a 12-inch wafer (radius 150mm) as an example, takes the chip on the wafer as a reference, and establishes a rectangular coordinate system with the center of the shielding plate as the origin. During alignment, the orthographic projection of the chip on the wafer on the shielding plate is symmetrically distributed in the four quadrants of the coordinate system about the X and Y axes.

[0041] In step S2, first, based on the wafer size, the maximum opening radius, chord length step, and maximum chord length of the shielding plate are set. That is, according to the process requirements, there is a non-electroplated area (about 2.5mm wide) at the edge of the 12-inch wafer, that is, the maximum opening radius needs to be limited to 147.5mm. Therefore, based on technical experience (based on considerations of the opening rate and number of openings of the shielding plate), the technical parameters of the shielding plate can be preliminarily set, that is, the maximum opening radius is 143mm, the initial chord length is 3.4mm, and the maximum chord length between adjacent holes in any layer is defined as 4.5mm, and the chord length step is 0.02mm (that is, the chord length between holes in each adjacent layer varies from the inside to the outside layer by layer with a difference of 0.02mm).

[0042] Secondly, based on the preliminarily set maximum opening radius, chord length step, and maximum chord length, this embodiment uses data processing tools (such as Excel software) to sequentially establish a mathematical model of the distance between the center of each circle of through holes and the origin of the coordinate system and a mathematical model of the offset angle of each circle of through holes relative to the X-axis, wherein the through holes of each circle are kept symmetrically distributed in the four quadrants of the coordinate system about the X and Y axes, and the offset angles of the corresponding through holes of each adjacent circle are kept to form a deviation. With the help of Excel software, it is only necessary to define the mathematical model of the first through hole to quickly synchronize the distance mathematical model and the offset angle mathematical model of the remaining through holes, and it is convenient to quickly summarize the total number of through holes, intersecting with the existing professional and complex data processing system. This embodiment is simple and convenient to operate, and the data processing is fast, which greatly improves efficiency.

[0043] In some specific embodiments, in the distance mathematical model, the number of through-hole circles and the radial distance between adjacent circles are first calculated, that is, the value of the through-hole circle number is calculated based on the maximum chord length. If the value is not an integer, the actual number of through-hole circles is the largest integer less than the value, and the actual radial distance between adjacent circles is calculated based on the largest integer. Here, each circle is numbered 1, 2, 3... from the inside to the outside; then, according to the number value of each circle and the radial distance of the adjacent circle, the distance from the center of each through-hole circle to the origin of the coordinate system is calculated. The distance calculation is a conventional geometric operation and will not be repeated here.

[0044] It should be noted that, in calculating the number of circles in this embodiment, reference is made to a conventional porous shielding plate with a honeycomb (regular hexagonal) layout, and the number of through-hole circles and the actual radial distance between adjacent circles are calculated based on the regular hexagonal structure and the above-mentioned maximum chord length. The calculation process is as follows:

[0045] D1=d0*cos30°(1);

[0046] n=r / D1(2);

[0047] D2=r / n(3);

[0048] In formulas (1) to (3), D1 is the maximum radial distance between adjacent ring layers based on the porous regular hexagonal layout, d0 is the maximum chord length, n is the actual number of through-hole rings (the largest integer less than the calculated result), r is the maximum opening radius of the shielding plate, and D2 is the actual radial distance between adjacent ring layers of the porous layout of this embodiment.

[0049] At the same time, in the mathematical model of the offset angle, the chord length between the through holes of each layer is first calculated based on the initial chord length and the chord length step (this is a conventional geometric operation and will not be described here); then, based on the number value of each layer, the actual radial distance and the chord length of each layer, the number of through holes in each layer and the radian between adjacent through holes are calculated; finally, the through holes in each layer are numbered 1, 2, 3... in sequence, and based on the number value and radian between each through hole, the offset angle of each through hole is calculated in sequence according to trigonometric functions.

[0050] In order to improve the accuracy of the calculation results, when calculating the number of through-holes in each circle layer, the shielding plate is divided into multiple areas with the center of the shielding plate as the center of the circle, and the number of through-holes in each circle layer in any area is calculated and the integer value is taken. The number of through-holes in each circle layer is calculated based on the integer value and the number of areas. The number of through-holes in each circle layer in a single area is calculated and the integer value is taken (the purpose is to eliminate the problem of non-integer values ​​that may appear when directly calculating the number of through-holes in the entire circle layer). Then, the number of through-holes is multiplied by the number of areas to obtain the accurate number of through-holes in each circle layer. The calculation formula is as follows:

[0051] a1=(2*π*n*D2) / d / t (4);

[0052] a2 = a1 * t (5);

[0053] In formulas (4) and (5), a1 is the number of through-holes in any region of the corresponding layer, rounded to an integer, n is the actual number of through-hole circles, D2 is the actual radial distance, d is the chord length of the corresponding layer, and t is the number of divided regions. In this embodiment, t = 4; a2 is the actual number of through-holes in the corresponding layer. Here, compared to directly calculating the number of through-holes in the entire layer and rounding it off, the calculation method of this application is more accurate and has smaller deviations. Moreover, based on the lack of data on the number of through-holes in each layer or the arc length between through-holes, this embodiment cleverly uses the chord length to more accurately and quickly calculate the number of through-holes in each layer.

[0054] At the same time, according to whether the number value of each circle layer is an even number or an odd number, the multiple circles of through holes are divided into multiple first circle groups and multiple second circle groups, wherein the multiple first circle groups and the multiple second circle groups are staggered in the radial direction of the shielding plate; processing polarities corresponding to the first circle group and the second circle group are set (for auxiliary calculation values ​​to achieve the staggered through holes of adjacent circle groups), and the offset angle of adjacent through holes in each circle layer is calculated based on the processing polarity, and the calculation formula is as follows:

[0055] θ=(N-1)*H+S*H / m (6)

[0056] In formula (6), θ is the offset angle of the through hole; N is the number of the through hole; H is the arc between holes; S is the processing polarity; m is 1 or an even number greater than 1.

[0057] In this embodiment, when calculating the offset angle of the through-holes in the first circle group, S = 1, and when calculating the offset angle of the through-holes in the second circle group, S = 0; m = 2. By grouping the through-holes and introducing machining polarity, the angular offset is strictly maintained when arranging multiple circles of holes. Furthermore, by limiting the value of m, the initial position through-holes of the corresponding circle layer are ensured to be symmetrical with the adjacent through-holes about the corresponding polar axis of the coordinate system. This allows positioning and machining of the remaining through-holes, starting with the initial position through-holes, to be continued, resulting in minimal deviation and high precision.

[0058] Then, based on the offset angle of each through hole and the radial distance from the origin, a mathematical model of the coordinate position of each through hole is established (which is a conventional trigonometric operation and will not be described here), and finally the coordinate position (x, y) of the center of each through hole is obtained.

[0059] Finally, combining the obtained coordinate positions of each through-hole and the simulation, analyze whether the distribution of the through-holes is symmetrical and matches the wafer chip distribution, and use simulation software to simulate the uniformity of the coating distribution. According to the analysis results, adjust the maximum opening radius or chord length step or maximum chord length, and repeat the above steps until the simulation coating distribution uniformity is optimal and determine the coordinate positions of each through-hole under this result.

[0060] In step S3, based on the coordinate positions of each through hole obtained in step S2, the tool is controlled to process the through holes one by one. The original angle of the tool's starting point relative to the X-axis is determined based on the coordinate system. Based on the original angle (used to determine the initial position of the tool before each machining operation) and the offset angle of each through hole (used to determine the rotation angle of the tool when it moves to the machining position), the through holes are machined sequentially. This facilitates precise machining of the through holes by the tool.

[0061] Furthermore, during processing, the diameters of the through holes on the shielding plate are equal. This layout of through holes with the same diameter allows for current density adjustment while also facilitating processing.

[0062] In summary, after adopting this positioning and processing method, first, with the chip on the wafer as the reference, a rectangular coordinate system with the center of the shielding plate as the origin is established. During alignment, the orthographic projection of the chip on the wafer on the shielding plate is symmetrically distributed in the four quadrants of the coordinate system about the X and Y axes; then, based on the wafer size, the maximum opening radius, chord length step, and maximum chord length of the shielding plate are set; then, based on the maximum opening radius, chord length step, and maximum chord length, a mathematical model of the distance between the center of each circle of through holes and the origin of the coordinate system and a mathematical model of the offset angle of each circle of through holes relative to the X axis or Y axis are successively established, wherein each circle is kept The through holes of the circle layers are symmetrically distributed in the four quadrants of the coordinate system about the X and Y axes, and the offset angles of the corresponding through holes of each adjacent circle layer are maintained to form a deviation. Based on the offset angles and radial distances of each through hole obtained, a mathematical model of the coordinate position of each through hole is established; combined with the obtained coordinate positions of each through hole and the simulation, the maximum opening radius or the chord length step or the maximum chord length is adjusted, and the above steps are repeated until the simulated coating distribution uniformity is optimal and the coordinate positions of each through hole under the result are determined; finally, based on the obtained coordinate positions of each through hole, the tool is controlled to process the through hole circle by circle. Therefore, compared with the prior art, the present invention, on the one hand, establishes a coordinate system on the shielding plate based on the chip layout on the wafer, and adjusts the initial calculation parameters based on the coordinate position of each through hole and the simulation, and finally controls the through hole distribution to match the wafer chip distribution, effectively improving the quality of the chip area plating; on the other hand, based on the angle deviation formed by the through holes of adjacent ring layers, it effectively avoids stress concentration during processing and improves the product yield; thirdly, compared with directly calculating the number of through holes in the entire ring layer and rounding it off, the calculation method of the present application is used to obtain the number of through holes more accurately and with smaller deviation; fourthly, by limiting the m value, it ensures that the initial position through holes of the corresponding ring layer and the adjacent through holes can be symmetrical about the corresponding polar axis of the coordinate system, so that the initial position through holes are used as the basis for continuing to position and process the remaining through holes, with small deviation and high precision; fifthly, with the help of Excel software, it is only necessary to define the mathematical model of the first through hole to quickly synchronize the distance mathematical model and the offset angle mathematical model of the remaining through holes, and it is convenient to quickly summarize the total number of through holes, which is simple and convenient to operate, and the data processing is fast, which greatly improves efficiency.

[0063] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for positioning and processing through holes on a wafer electroplating shielding plate, which is used for positioning and processing multiple circles of through holes distributed sequentially from the inside to the outside on the shielding plate, characterized in that: Each circle of through holes is distributed in an array around the central circumference of the shielding plate, and the chord length between adjacent holes in each circle increases step by step from the inside to the outside, and the chord length steps are equal. The method includes the following steps: S1. Establish a coordinate system Taking the chip on the wafer as the reference, establish a rectangular coordinate system with the center of the shielding plate as the origin. During alignment, the orthographic projection of the chip on the wafer on the shielding plate is symmetrically distributed in the four quadrants of the coordinate system about the X and Y axes. S2. Calculate the coordinate position of each hole 1) Based on the wafer size, set the maximum opening radius, chord length step, and maximum chord length of the shielding plate; 2) Based on the maximum opening radius, chord length step, and maximum chord length, mathematical models are established for the distance between the center of each circle of through holes and the origin of the coordinate system, as well as the offset angle of each circle of through holes relative to the X-axis or Y-axis. The through holes of each circle are symmetrically distributed in the four quadrants of the coordinate system about the X and Y axes, and the offset angles of corresponding through holes in each adjacent circle are maintained to form a deviation. 3) establishing a coordinate position mathematical model of each through hole based on the obtained offset angle and radial distance of each through hole; 4) Based on the obtained coordinate positions of each through hole and the simulated coating distribution, adjust the maximum opening radius or chord length step or maximum chord length in step 1), and repeat steps 2) and 3) until the simulated coating distribution uniformity is optimal and determine the coordinate positions of each through hole based on the result; S3, Processing Based on the coordinate position of each through hole obtained in step S2, the tool is controlled to process the through holes circle by circle.

2. The method for positioning and processing through holes on a wafer electroplating shielding plate according to claim 1, characterized in that: In the distance mathematical model, the number of through-hole circles and the radial distances between adjacent circles are first calculated, where the circles are numbered 1, 2, 3, etc. from the inside out. Then, based on the number of each circle and the radial distances between adjacent circles, the distance from the center of each through-hole circle to the origin of the coordinate system is calculated.

3. The method for positioning and processing through holes on a wafer electroplating shielding plate according to claim 2, characterized in that: The value of the number of through-hole turns is calculated based on the maximum chord length, and then the actual number of through-hole turns is taken as the largest integer smaller than the value, and the actual radial distance between adjacent layers is calculated based on the largest integer.

4. The method for positioning and processing through holes on a wafer electroplating shielding plate according to claim 3, characterized in that: In the offset angle mathematical model, the chord length between the through-holes in each layer is first calculated. Then, based on the number of each layer, the actual radial distance, and the chord length of each layer, the number of through-holes in each layer and the arc between adjacent through-holes are calculated. Finally, the through-holes in each layer are numbered 1, 2, 3, etc., and the offset angle of each through-hole is calculated based on the number of each through-hole and the arc between the holes.

5. The method for positioning and processing through holes on a wafer electroplating shielding plate according to claim 4, characterized in that: When calculating the number of through holes in each circle layer, the shielding plate is divided into multiple areas with the center of the shielding plate as the center of the circle, and the number of through holes in each circle layer in any area is calculated and taken as an integer value. The number of through holes in each circle layer is then calculated based on the integer value and the number of areas.

6. The method for positioning and processing through holes on a wafer electroplating shielding plate according to claim 4, characterized in that: The multiple-circle through holes are divided into multiple first circle groups and multiple second circle groups, wherein the multiple first circle groups and the multiple second circle groups are staggered in the radial direction of the shielding plate; processing polarities corresponding to the first circle group and the second circle group are set, and the offset angle is calculated based on the processing polarity, and the calculation formula is as follows: θ=(N-1)*H+S*H / m; Where θ is the offset angle of the through hole, N is the number of the through hole, H is the arc between holes, S is the processing polarity, and m is 1 or an even number greater than 1.

7. The method for positioning and processing through holes on a wafer electroplating shielding plate according to claim 6, characterized in that: When calculating the offset angle of the through holes of the first circle group, S=1, and when calculating the offset angle of the through holes of the second circle group, S=0; and / or, m=2.

8. The method for positioning and processing through holes on a wafer electroplating shielding plate according to claim 1, characterized in that: In step S3, the coordinate system is used as a reference to determine the original angle of the tool starting point relative to the X or Y axis, and the through holes are processed sequentially based on the original angle and the offset angle of each through hole.

9. A shielding plate for wafer electroplating, characterized in that: The positioning device is made by the positioning and processing method according to any one of claims 1 to 8.

10. The method for positioning and processing through holes on a wafer electroplating shielding plate according to claim 9, characterized in that: The apertures of the through holes on the shielding plate are equal.

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