Wafer positioning method, system, chemical mechanical polishing apparatus, and storage medium

Abstract

The present application provides a wafer positioning method and system, and a chemical mechanical polishing device. The wafer positioning method comprises the following steps: collecting distance data of multiple positions of a wafer edge to a rotation center of a motion stage via a linear sensor; analyzing the distance data to extract edge region data and notch region data; determining an offset of a centroid of the wafer relative to the rotation center of the motion stage according to the edge region data; analyzing the notch region data to determine a first deflection angle of a notch direction of the wafer relative to a preset translation direction of the motion stage; determining a corresponding positioning compensation according to the offset, the first deflection angle, and a second deflection angle of the linear sensor relative to the preset translation direction of the motion stage, and using the positioning compensation to compensate a measurement coordinate of a measurement point in a coordinate system of the motion stage to determine a real coordinate of the measurement point in the coordinate system of the motion stage.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a wafer positioning method, a wafer positioning system, a chemical mechanical polishing apparatus, and a computer-readable storage medium. Background Technology

[0002] Chemical Mechanical Polishing (CMP) equipment is one of the key process equipment in semiconductor manufacturing. With the development of chip manufacturing technology, the use of CMP in integrated circuit manufacturing has rapidly increased, leading to continuously rising performance requirements for CMP equipment. However, existing CMP equipment typically lacks film thickness measurement capabilities, necessitating the use of mounted film thickness measurement units to characterize the polished thickness and / or flatness of the CMP process. However, the measurement accuracy of the film thickness measurement unit is closely related to the wafer positioning accuracy. Traditional measurement equipment relies on a pre-calibration module in the Equipment Front End Module (EFEM) for wafer positioning, and the wafer positioning orientation is closely related to the installation position of the positioning sensor. Due to mechanical errors in the pre-calibration module, the wafer positioning result includes an unknown error angle, affecting the accuracy of wafer positioning. Furthermore, this positioning method requires multiple wafer pick-up and drop operations and calculations during the positioning process, resulting in low efficiency.

[0003] In order to overcome the above-mentioned defects in the existing technology, there is an urgent need in the field for an improved wafer positioning method to improve the efficiency of wafer measurement and the accuracy of wafer positioning in chemical mechanical polishing processes. Summary of the Invention

[0004] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed descriptions that follow.

[0005] To overcome the aforementioned deficiencies in the prior art, this invention provides a wafer positioning method, a wafer positioning system, a chemical mechanical polishing apparatus, and a computer-readable storage medium. This invention not only determines the wafer's offset and first deflection angle relative to the motion stage based on multiple marks on a standard wafer, but also determines the second deflection angle between the linear sensor and the preset translation direction of the motion stage. This allows for more efficient and accurate compensation of the coordinates of the measurement points in the motion stage coordinate system, thereby improving the efficiency of wafer measurement and the accuracy of wafer positioning.

[0006] Specifically, the wafer positioning method provided by the first aspect of the present invention includes the following steps: placing the wafer to be positioned on a motion stage and rotating the motion stage to collect distance data from multiple positions of the wafer edge to the rotation center of the motion stage via a linear sensor; parsing the distance data from the multiple positions to the rotation center of the motion stage to extract edge region data and notch region data therein; determining the offset (X0, Y0) of the centroid of the wafer relative to the rotation center of the motion stage based on the edge region data; and parsing the notch region data to determine its center point coordinates. (X1,Y1), and combined with the offset (X0,Y0), determine the first deflection angle θ between the notch orientation of the wafer and the preset translation direction of the motion stage; based on the offset (X0,Y0), the first deflection angle θ, and the second deflection angle Δθ between the linear sensor and the preset translation direction of the motion stage, determine the corresponding positioning compensation amount (x′,y′); and use the positioning compensation amount (x′,y′) to compensate for the measurement coordinates (x,y) of the measurement point in the motion stage coordinate system, to determine the true coordinates (x,y) of the measurement point in the motion stage coordinate system. c ,y c ).

[0007] Furthermore, in some embodiments of the present invention, before acquiring distance data from multiple locations on the wafer edge to the rotation center of the motion stage, the wafer positioning method further includes the following steps: adsorbing a standard wafer onto the motion stage, wherein the center of the detection surface of the standard wafer has a first mark; moving the motion stage to move the center of the first mark to the rotation center of the motion stage, and rotating the motion stage to acquire induced voltages at multiple locations on the edge of the standard wafer via the linear sensor; and based on the distance R from the edge region of the standard wafer to its centroid, and the average value V of the induced voltages acquired by the linear sensor at each of the aforementioned locations on the edge region. avr The correspondence between the induced voltage and the distance is calibrated.

[0008] Further, in some embodiments of the present invention, the step of moving the motion stage to move the center of the first mark to the rotation center of the motion stage includes: initially moving the motion stage to move the first mark to the field of view of a camera, and rotating the motion stage by a preset first step length to acquire multiple calibration images via the camera; parsing each calibration image to determine the center coordinates (x, y, x) of the center of the first mark in the corresponding calibration image. i ,y i ); for each of the stated center coordinates (x i ,y i Fitting is performed to determine the rotation center coordinates of the motion stage in the camera coordinate system; and based on the rotation center coordinates, the motion stage is moved again to move the center of the first mark to the rotation center of the motion stage.

[0009] Furthermore, in some embodiments of the present invention, the length of the first step is no greater than 360 / m°, the number of calibration images acquired is no less than m, and the process of adjusting the center coordinates (x...) i ,y i The step of fitting the coordinates of the rotation center of the motion platform in the camera coordinate system includes: constructing a system of least squares fitting equations for the rotation center coordinates:

[0010]

[0011] Where A and B indicate the offset of the rotation center coordinates. C indicates the radius of the circle corresponding to the rotation center coordinates; and the center coordinates (x, y) of the center of the first mark in each calibration image. i ,y i Substitute these values ​​into the least squares fitting equations to determine the rotation center coordinates of the motion platform in the camera coordinate system.

[0012] Further, in some embodiments of the present invention, the step of rotating the motion stage to collect distance data from multiple positions on the wafer edge to the rotation center of the motion stage includes: rotating the motion stage by a preset second step size to obtain the induced voltages when the linear sensor collects data at n positions on the wafer edge. The second step size is no greater than 0.2°. n is a natural number not less than 1800; and substituting the induced voltages collected by the linear sensor at each of the aforementioned positions on the wafer edge into the correspondence between the induced voltage and the distance, respectively, to determine the distance data from each of the aforementioned positions on the wafer edge to the rotation center of the motion stage.

[0013] Further, in some embodiments of the present invention, the length of the linear sensor along the radial direction of the wafer is L. The step of determining the distance data from each position on the wafer edge to the rotation center of the motion stage by substituting the induced voltage obtained by the linear sensor at each of the stated positions on the wafer edge into the correspondence between the induced voltage and the distance includes: based on the induced voltage V1 to V2 obtained by the linear sensor at each of the stated positions on the wafer edge... n Determine the minimum value V among them. min and maximum value V max ; and the induced voltages V1 to V n Substitute them into the following conversion formulas respectively:

[0014]

[0015] To determine the distances R1 to R2 from each of the said positions on the wafer edge to the rotation center of the motion stage. n .

[0016] Furthermore, in some embodiments of the present invention, the step of parsing the distance data from the plurality of locations to the rotation center of the motion stage to extract edge region data and notch region data includes: calculating the distances R1 to R2 from the plurality of locations on the wafer edge to the rotation center of the motion stage. n Perform difference operations on adjacent positions to determine a difference array (Diff1, Diff2, ..., Diff...). n ),in, A division threshold is determined based on the standard deviation of each element in the difference array; the difference array is traversed to determine the start and end points of the notch region at the wafer edge according to the division threshold; the distance R from the start point, the end point, and each position in between to the rotation center of the motion stage is determined based on these distances. start ~R end Determine the data for the gap region; and determine the distances R1 to R2 from each position outside the gap region to the rotation center of the motion table. start-1 and R end+1 ~R n The edge region data is determined.

[0017] Further, in some embodiments of the present invention, the step of traversing the difference array to determine the start and end points of the notch region at the wafer edge according to the partitioning threshold includes: traversing the difference array and comparing the value of each element therein with the partitioning threshold; responding to the value of any element Diff startIf the value of an element is greater than the threshold, and the values ​​of the preceding preset number of elements are all less than the threshold, the position corresponding to that element is determined as the starting point of the gap region; and in response to the value Diff of any of the elements... end If the value of an element is greater than the threshold, and the value of a predetermined number of subsequent elements is less than the threshold, the position corresponding to that element is determined as the end point of the gap region.

[0018] Furthermore, in some embodiments of the present invention, the step of parsing the gap region data to determine its center point coordinates (X1, Y1) includes: determining the distance R from each of the positions in the edge region to the rotation center of the motion table. start ~R end And the corresponding rotation angle of the motion table, to determine the X-axis projection x of each position in the edge region onto the motion table coordinate system. start ~x end and Y-axis projection y start ~y end According to the X-axis projection amount x start ~x end Construct an array of independent variables, and based on the Y-axis projection y... start ~y end Construct an array of dependent variables to generate the following system of linear equations:

[0019]

[0020] Where m is the amount of data in the edge region. i and j are the powers of the independent variables in the system of linear equations. G ij and G im The elements are the coefficient matrix of the linear equation system; and the linear equation system is solved using Gaussian elimination to calculate the parameters of the corresponding quadratic fitting curve, so as to determine the center point coordinates (X1, Y1) of the gap region based on the minimum value of the quadratic fitting curve.

[0021] Further, in some embodiments of the present invention, the step of determining the offset (X0, Y0) of the centroid of the wafer relative to the rotation center of the motion stage based on the edge region data includes: arbitrarily selecting three positions from the edge region data, and determining the center coordinates (x0, y0) of the circle formed by the three positions in the motion stage coordinate system based on their distances to the rotation center of the motion stage and the corresponding rotation angle of the motion stage; and constructing an iterative optimization function of the LM algorithm using the center coordinates (x0, y0) as the initial position parameter P0, and calculating the optimal solution of the iterative optimization based on the chi-square value of the center coordinates before and after the iterative optimization, so as to determine the offset (X0, Y0) of the centroid of the wafer relative to the rotation center of the motion stage.

[0022] Furthermore, in some embodiments of the present invention, the iterative optimization function is expressed as:

[0023]

[0024] Among them, P k and P k+1 These are the position parameters obtained in the k-th and (k+1)-th iterations, respectively. k It is the Jacobian matrix formed by calculating the partial derivatives of the residuals with respect to the position parameters. λ is the damping coefficient that adjusts the iteration rate. I is the identity matrix.

[0025] The formula for calculating the chi-square value is:

[0026]

[0027] Where Chisq is the chi-square value, n is the number of positions of the wafer edge collected by the linear sensor, and k is a natural number (x k+1 ,y k+1 ) represents the position parameter P k+1 The coordinate representation of P k+1 For position parameter P k+1 The radius is represented by .

[0028] Furthermore, in some embodiments of the present invention, the step of calculating the optimal solution of the iterative optimization based on the chi-square value of the center coordinates before and after iterative optimization, and determining the offset (X0, Y0) of the centroid of the wafer relative to the rotation center of the motion stage, includes: calculating the chi-square value Chisq after the current iteration. k+1 Chisq, the chi-square value after the previous iteration k Comparison; responding to the chi-square value Chisq after this iteration k+1 Chisq, which is less than the chi-square value after the previous iteration k The damping coefficient is reduced to allow for the next round of iteration optimization; this is in response to the chi-square value Chisq after this iteration. k+1 Chisq is greater than or equal to the chi-square value after the previous iteration. k Increase the damping coefficient for the next iteration of optimization; and respond to the chi-square value Chisq after this iteration. k+1 If the value is less than the preset chi-square threshold, the position parameter P obtained from this iteration is used. k+1 Determine the offset (X0, Y0) of the centroid of the wafer relative to the rotation center of the motion stage.

[0029] Furthermore, in some embodiments of the present invention, a second mark is also formed on the edge of the standard wafer. The second mark is located on the extension line connecting the center of the notch of the standard wafer and the first mark. Before collecting distance data from multiple positions of the wafer edge to the rotation center of the motion stage, the wafer positioning method further includes the following steps: after moving the center of the first mark to the rotation center of the motion stage, the motion stage is initially rotated to move the second mark to the center of the camera's field of view, and the rotation angle θ0 of the motion stage at this time is recorded; the motion stage is rotated again to collect distance data from multiple positions of the standard wafer edge to the rotation center of the motion stage via the linear sensor, and the distance data is analyzed to determine the deflection angle θ1 of the notch orientation of the standard wafer and the preset translation direction of the motion stage; and based on the rotation angle θ0 and the deflection angle θ1, a second deflection angle Δθ of the linear sensor and the preset translation direction of the motion stage is determined.

[0030] Furthermore, in some embodiments of the present invention, the first deflection angle θ is expressed as:

[0031]

[0032] The positioning compensation amount (x′, y′) is expressed as:

[0033]

[0034] The true coordinates (x) c ,y c ) is represented as:

[0035] x c =x+x′

[0036] y c =y+y′.

[0037] Furthermore, the wafer positioning system provided according to a second aspect of the present invention includes a memory and a processor. The memory stores computer instructions. The processor is connected to the memory and is used to execute the computer instructions stored in the memory to implement the wafer positioning method as provided in the first aspect of the present invention.

[0038] Furthermore, the chemical mechanical polishing (CMP) apparatus provided according to a third aspect of the present invention includes a polishing mechanism, a film thickness measurement unit, and a wafer positioning system as provided in a second aspect of the present invention. The polishing mechanism is used to perform a CMP process on a wafer to be processed. The film thickness measurement unit is used to determine the film thickness at multiple measurement points on the wafer surface. The wafer positioning system is used to determine the true coordinates of each measurement point to cooperate with the film thickness measurement unit in characterizing the polishing thickness and / or polishing flatness of the CMP process.

[0039] Furthermore, the computer-readable storage medium provided according to the fourth aspect of the present invention stores computer instructions thereon. When the computer instructions are executed by a processor, the wafer positioning method as provided in the first aspect of the present invention is implemented. Attached Figure Description

[0040] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0041] Figure 1 A schematic flowchart of a wafer positioning method provided according to some embodiments of the present invention is shown.

[0042] Figure 2 A schematic diagram of a wafer placed on a motion stage according to some embodiments of the present invention is shown.

[0043] Figure 3 A schematic diagram of a first mark provided according to some embodiments of the present invention is shown.

[0044] Figure 4 A schematic diagram is shown of a first marker moving to the center of rotation of a motion table according to some embodiments of the present invention.

[0045] Figure 5 A schematic diagram of acquiring multiple locations at the edge of a wafer according to some embodiments of the present invention is shown.

[0046] Figure 6 A schematic diagram illustrating the principle of determining the offset of the centroid of a wafer relative to the rotation center of the stage, according to some embodiments of the present invention, is shown.

[0047] Figure 7 A schematic diagram of a second mark provided according to some embodiments of the present invention is shown.

[0048] Figure 8 A schematic diagram is shown showing a second marker moving to the center of the camera's field of view, according to some embodiments of the present invention.

[0049] Figure 9 A schematic diagram illustrating the principle of wafer positioning compensation based on a second mark according to some embodiments of the present invention is shown. Detailed Implementation

[0050] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a thorough understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] Furthermore, the terms "upper," "lower," "left," "right," "top," "bottom," "horizontal," and "vertical" used in the following description should be understood as the orientations shown in the relevant paragraphs and accompanying drawings. These relative terms are for illustrative purposes only and do not imply that the described apparatus must be manufactured or operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0053] It is understood that although terms such as "first," "second," and "third" may be used herein to describe various components, regions, layers, and / or parts, these components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers, and / or parts. Therefore, the first components, regions, layers, and / or parts discussed below may be referred to as second components, regions, layers, and / or parts without departing from some embodiments of the present invention.

[0054] As mentioned above, existing chemical mechanical polishing (CMP) equipment typically lacks film thickness measurement capabilities. Therefore, a mounted film thickness measurement unit is required to characterize the polishing thickness and / or flatness of the CMP process. However, the measurement accuracy of the film thickness measurement unit is closely related to the wafer positioning accuracy. Traditional measurement equipment relies on a pre-calibration module in the Equipment Front End Module (EFEM) for wafer positioning, and the wafer positioning orientation is closely related to the installation position of the positioning sensor. Due to mechanical errors in the pre-calibration module, the wafer positioning result includes an unknown error angle, thus affecting the accuracy of wafer positioning. Furthermore, this positioning method requires multiple wafer handling and calculations during the positioning process, resulting in low efficiency.

[0055] To overcome the aforementioned deficiencies in the prior art, this invention provides a wafer positioning method, a wafer positioning system, a chemical mechanical polishing apparatus, and a computer-readable storage medium. This invention not only determines the wafer's offset and first deflection angle relative to the motion stage based on multiple marks on a standard wafer, but also determines the second deflection angle between the linear sensor and the preset translation direction of the motion stage. This allows for more efficient and accurate compensation of the coordinates of the measurement points in the motion stage coordinate system, thereby improving the efficiency of wafer measurement and the accuracy of wafer positioning.

[0056] In some non-limiting embodiments, the wafer positioning system provided in the second aspect of the present invention can be configured within the chemical mechanical polishing (CMP) apparatus provided in the third aspect of the present invention. Specifically, the CMP apparatus includes a polishing mechanism, a film thickness measurement unit, and the wafer positioning system provided in the second aspect of the present invention. Here, the polishing mechanism is used to perform a CMP process on the wafer to be processed. The film thickness measurement unit is used to determine the film thickness at multiple measurement points on the wafer surface. The wafer positioning system is used to determine the true coordinates of each measurement point to cooperate with the film thickness measurement unit in characterizing the polishing thickness and / or polishing flatness of the CMP process.

[0057] In addition, in some optional embodiments, those skilled in the art can also integrate the wafer positioning system provided in the second aspect of the present invention into a film thickness measurement machine to meet the film thickness measurement needs of other equipment.

[0058] Furthermore, the wafer positioning system provided in the second aspect of the present invention includes a memory and a processor. Here, the memory includes, but is not limited to, the computer-readable storage medium provided in the third aspect, on which computer instructions are stored. The processor is connected to the memory and configured to execute the computer instructions stored in the memory to implement the wafer positioning method as provided in the first aspect of the present invention.

[0059] The working principle of the wafer positioning system described above will be described below with reference to some embodiments of wafer positioning methods. Those skilled in the art will understand that these embodiments of wafer positioning methods are merely non-limiting implementations provided by the present invention, intended to clearly demonstrate the main concepts of the invention and provide specific solutions convenient for public implementation, rather than limiting all functions or all operating methods of the wafer positioning system. Similarly, this wafer positioning system is also only one non-limiting implementation provided by the present invention, and does not limit the executing entity or execution order of the steps in these wafer positioning methods.

[0060] Please refer to the reference. Figure 1 and Figure 2 . Figure 1 A schematic flowchart of a wafer positioning method provided according to some embodiments of the present invention is shown. Figure 2 A schematic diagram of a wafer placed on a motion stage according to some embodiments of the present invention is shown.

[0061] like Figure 1 and Figure 2 As shown, the wafer positioning system can first place the wafer 11 to be positioned on the motion stage 12 and rotate the motion stage 12 to collect distance data from multiple positions on the edge of the wafer 11 to the rotation center 13 of the motion stage.

[0062] Furthermore, such as Figure 2 As shown, during the process of adsorbing wafer 11 onto the motion stage 12, the wafer positioning system can place wafer 11 among the four gradient pillars of the motion stage 12, and wafer 11 will slide down onto the wafer carrier stage through the pillars. Afterwards, the wafer positioning system can control the motion stage 12 to vacuum adsorb wafer 11, so as to use the pillar structure to initially control the circumferential error of wafer 11 on the motion stage 12.

[0063] Please refer to the reference. Figure 3 and Figure 4 . Figure 3 A schematic diagram of a first mark provided according to some embodiments of the present invention is shown. Figure 4 A schematic diagram is shown of a first marker moving to the center of rotation of a motion table according to some embodiments of the present invention.

[0064] Furthermore, in some preferred embodiments, before acquiring the aforementioned distance data, the wafer positioning system can first use a standard wafer with a first mark on its surface to calibrate the correspondence between the induced voltage at multiple positions on the edge of the standard wafer acquired by the linear sensor 14 and the distance from the edge region to its centroid.

[0065] Specifically, the wafer positioning system can first attach a standard wafer with a first mark made in the center of the detection surface to the motion stage 12. Here, the first mark is a specific standardized graphic structure made on the surface of the standard wafer through processes such as photolithography, including but not limited to geometric shapes such as lines, blocks, and holes, and the size, shape, spacing and other parameters of these graphics can be made according to a pre-set standard.

[0066] Furthermore, in Figure 3 In the embodiment shown, the first marker is a four-leaf clover graphic.

[0067] After that, as Figure 4 As shown, the wafer positioning system can move the stage 12 to move the center of the first mark to the rotation center 13 of the stage, and rotate the stage 12 to acquire the induced voltage at multiple positions on the edge of the standard wafer via the CCD (Charge Coupled Device) linear sensor 14 and the high-speed I / O digital acquisition card.

[0068] Furthermore, during the process of moving the center of the first mark to the rotation center 13 of the motion stage, the wafer positioning system can first move the motion stage 12 to move the first mark to the field of view of a camera (not shown), and then rotate the motion stage 12 according to a preset first step length to acquire multiple calibration images.

[0069] Subsequently, the processor of the wafer positioning system can analyze each calibration image to determine the center coordinates (x, y) of the first marker within it. i ,y i ).

[0070] Then, the processor can process the center coordinates (x... i ,y i Fitting is performed to determine the rotation center coordinates of the motion stage 13 in the camera coordinate system, and the motion stage 12 is moved again according to the rotation center coordinates to move the center of the first mark to the rotation center 13 of the motion stage.

[0071] Furthermore, in some embodiments, the length of the first step described above is no greater than 360 / m°, and the number of calibration images acquired is no less than m. For example, when m = 12, the processor can construct a system of least squares fitting equations for the coordinates of the rotation center as follows:

[0072]

[0073] Where A and B indicate the offset of the rotation center coordinates, and C indicates the radius of the circle corresponding to the rotation center coordinates.

[0074] Then, the processor can determine the center coordinates (x, y) of the first marker in each calibrated image. i ,y i Substitute these equations into the least squares fitting system to determine the coordinates of the rotation center 13 of the motion platform in the camera coordinate system.

[0075] Then, the processor can determine the distance R from the edge region of the standard wafer to its centroid, and the average value V of the induced voltage at various locations of the edge region collected by the linear sensor 14. avr The relationship between induced voltage and distance was calibrated.

[0076] Please refer to Figure 5 . Figure 5 A schematic diagram of acquiring multiple locations at the edge of a wafer according to some embodiments of the present invention is shown.

[0077] After that, such as Figure 5 As shown, during the process of acquiring distance data from multiple locations on the edge of wafer 11 to the rotation center 13 of the motion stage, the wafer positioning system can rotate the motion stage 12 by a preset second step size to acquire the induced voltage at n locations on the edge of wafer 11 via the linear sensor 14 and the high-speed I / O digital acquisition card. Here, the second step size is no greater than 0.2° (e.g., 0.18°), and n is a natural number not less than 1800 (e.g., 2000).

[0078] Subsequently, the processor of the wafer positioning system can use the linear sensor 14 to collect the induced voltage at each position on the edge of the wafer 11, and substitute it into the correspondence between the induced voltage and the distance to determine the distance data from each position on the edge of the wafer 11 to the rotation center 13 of the motion stage.

[0079] Furthermore, in Figure 2 and Figure 5 In the illustrated embodiment, the linear sensor 14 has a radial length of L along the wafer 11. Here, the processor can obtain the induced voltages V1 to V2 obtained by the linear sensor 14 at various locations along the edge of the wafer 11. n Determine the minimum value V among them. min and maximum value V max .

[0080] Then, the processor can convert each induced voltage V1 to V... n Substitute them into the following conversion formulas respectively:

[0081]

[0082] To determine the distances R1 to R2 from each position on the edge of wafer 11 to the rotation center of the stage. n .

[0083] Then, the processor can parse the distance data from the above multiple positions to the rotation center 13 of the motion table to extract the edge region data and the gap region data.

[0084] Specifically, the processor can measure the distances R1 to R2 from multiple locations on the edge of wafer 11 to the rotation center 13 of the motion stage. n Perform difference operations on adjacent positions to determine a difference array (Diff1, Diff2, ..., Diff...). n Here,

[0085] The processor can then determine a splitting threshold (e.g., 3σ) based on the standard deviation of each element in the difference array.

[0086] Then, the processor can traverse the difference array to determine the start and end points of the notch region at the edge of wafer 11 based on the aforementioned partitioning threshold.

[0087] Specifically, the processor can compare the value of each element in the difference array with the aforementioned dividing threshold while iterating through the difference array.

[0088] Then, in response to the value of any element, Diff start If the value of an element is greater than the dividing threshold, and the values ​​of the previous preset number of elements (e.g., 3) are all less than the dividing threshold, the processor can determine the position corresponding to that element as the starting point of the gap region.

[0089] Alternatively, responding to the value of any element, Diff end If the value of an element is greater than the threshold, and the value of the next preset number (e.g., 3) of elements is less than the threshold, the processor can determine the position corresponding to that element as the end point of the gap region.

[0090] Then, the processor can determine the distance R from the start point, the end point, and the positions in between to the rotation center 13 of the motion table. start ~R end Determine the data for the gap area, and based on the distances R1 to R2 from each position outside the gap area to the rotation center 13 of the motion table... start-1 and R end+1 ~R n Determine the edge region data.

[0091] Please refer to Figure 6 . Figure 6 A schematic diagram illustrating the principle of determining the offset of the centroid of a wafer relative to the rotation center of the stage, according to some embodiments of the present invention, is shown.

[0092] After that, such as Figure 6As shown, the processor can determine the offset (X0, Y0) of the centroid 111 of wafer 11 relative to the rotation center 13 of the motion stage based on the edge region data.

[0093] Specifically, the processor can arbitrarily select three positions (x1, y1), (x2, y2), and (x3, y3) from the edge region data, and determine the center coordinates (x0, y0) of the circle formed by the three positions in the motion table coordinate system based on their distances to the rotation center 13 of the motion table and the corresponding rotation angle of the motion table 12.

[0094]

[0095] in,

[0096] The processor can then calculate the wafer radius r:

[0097]

[0098] Then, the processor can construct the iterative optimization function of the LM algorithm with the center coordinates (x0, y0) as the initial position parameter P0, and calculate the optimal solution of the iterative optimization based on the chi-square value of the center coordinates before and after the iterative optimization, so as to determine the offset (X0, Y0) of the centroid of the wafer 11 relative to the rotation center 13 of the motion stage.

[0099] Furthermore, in some embodiments, the above iterative optimization function is expressed as:

[0100]

[0101] Among them, P k and P k+1 These are the position parameters obtained in the k-th and (k+1)-th iterations, respectively. λ is the damping coefficient that adjusts the iteration speed, and I is the identity matrix. J k The Jacobian matrix is ​​formed by calculating the partial derivatives of the residuals with respect to the position parameters; here, it represents the partial derivatives obtained using the central difference method.

[0102]

[0103] Where f is the residual calculation function and h is the step size of the position parameter P.

[0104] Furthermore, in some embodiments, the formula for calculating the chi-square value is as follows:

[0105]

[0106] Where Chisq is the chi-square value, n is the number of positions of the wafer edge collected by the linear sensor, and k is a natural number (x k+1,y k+1 ) represents the position parameter P k+1 The coordinate representation of R k+1 For position parameter P k+1 The radius is represented by .

[0107] Furthermore, in the process of iteratively determining the offset (X0, Y0) of the centroid 111 of wafer 11 relative to the rotation center 13 of the motion stage, the wafer positioning system can use the chi-square value Chisq after this round of iteration. k+1 Chisq, the chi-square value after the previous iteration k Compare them.

[0108] Then, responding to the chi-square value Chisq after this iteration k+1 Chisq, which is less than the chi-square value after the previous iteration k The processor can determine that the current iteration is valid, and thus reduce the damping coefficient (e.g., λ = 0.1*λ) to proceed with the next iteration optimization.

[0109] Alternatively, responding to the chi-square value Chisq after this iteration. k+1 Chisq is greater than or equal to the chi-square value after the previous iteration. k The processor can determine that the current iteration is invalid, and thus increase the damping coefficient (e.g., λ = 10*λ) to perform the next iteration optimization.

[0110] Alternatively, the response to the chi-square value Chisq after this iteration. k+1 Less than the preset chi-square threshold (e.g., 10) -7 The processor can determine that it has found the optimal solution, and then use the position parameters P obtained in this iteration to determine the optimal solution. k+1 Determine the offset (X0, Y0) of the centroid 111 of wafer 11 relative to the rotation center 13 of the motion stage.

[0111] After that, such as Figure 6 As shown, the processor can parse the data of the gap region to determine the coordinates (X1, Y1) of its center point 112.

[0112] Specifically, the processor can determine the distance R from each location in the edge region to the rotation center 13 of the motion table. start ~R end And the corresponding rotation angle of the motion table 12, to determine the X-axis projection x of each position in the edge region onto the motion table coordinate system. start ~x end and Y-axis projection y start ~y end .

[0113] Then, the processor can determine the X-axis projection amount x. start ~xend Construct an array of independent variables and calculate based on the Y-axis projection y. start ~y end Construct an array of dependent variables to generate the following system of linear equations:

[0114]

[0115] Where m is the amount of data in the marginal region, i and j are the powers of the independent variables in the linear equation system, and G ij and G im are elements in the coefficient matrix of the linear system of equations.

[0116] Then, the wafer positioning system can use Gaussian elimination to solve the linear equation system and calculate the parameters of the corresponding quadratic fitting curve, so as to determine the coordinates (X1, Y1) of the center point 112 of the notch region based on the minimum value of the quadratic fitting curve.

[0117] Subsequently, the wafer positioning system can determine the first deflection angle θ between the wafer notch orientation and the preset translation direction of the motion stage 12 based on the center point coordinates (X1, Y1) of the notch area and the offset (X0, Y0).

[0118] Please refer to the reference. Figures 7-9 . Figure 7 A schematic diagram of a second mark provided according to some embodiments of the present invention is shown. Figure 8 A schematic diagram is shown showing a second marker moving to the center of the camera's field of view, according to some embodiments of the present invention. Figure 9 A schematic diagram illustrating the principle of wafer positioning compensation based on a second mark according to some embodiments of the present invention is shown.

[0119] In addition, Figure 7 In the embodiment shown, a second mark is also made on the edge of the standard wafer, and the second mark is located on the extension line connecting the notch center 112 of the standard wafer and the first mark.

[0120] like Figure 7 and Figure 8 As shown, before acquiring distance data, the wafer positioning system can also rotate the motion stage 12 for the first time after moving the center of the first marker to the rotation center of the motion stage 12, so as to move the second marker to the center of the camera field of view 81, and record the rotation angle θ0 of the motion stage 12 at this time.

[0121] Afterwards, the wafer positioning system can rotate the stage 12 again to collect distance data from multiple positions on the edge of the standard wafer to the rotation center 13 of the stage, and analyze the distance data to determine the deflection angle θ1 of the notch orientation of the standard wafer and the preset translation direction of the stage 12.

[0122] After that, such as Figure 9 As shown, the wafer positioning system can determine the second deflection angle Δθ = θ0 + θ1 of the preset translation direction between the linear sensor 14 and the motion stage 12 based on the rotation angle θ0 and the deflection angle θ1.

[0123] Subsequently, the wafer positioning system can determine the corresponding positioning compensation amount (x′, y′) based on the offset (X0, Y0) of the wafer's centroid 111 relative to the rotation center 13 of the motion stage, the first deflection angle θ of the wafer 11's notch orientation relative to the preset translation direction of the motion stage 12, and the second deflection angle Δθ of the linear sensor 14 relative to the preset translation direction of the motion stage 12.

[0124]

[0125] Wherein, the first deflection angle θ between the notch of wafer 11 and the preset translation direction of motion stage 12 is expressed as:

[0126] During wafer measurement, the processor can use the positioning compensation (x′, y′) to compensate for the measurement coordinates (x, y) of the measurement point in the motion stage coordinate system, thereby determining the true coordinates (x, y) of the measurement point in the motion stage coordinate system. c ,y c ):

[0127] x c =x+x′

[0128] y c =y+y′

[0129] Thus, the wafer positioning method provided by the first aspect of the present invention can again compensate for the measurement coordinates of the measurement point based on the second mark, so as to compensate for the second deflection angle Δθ of the preset translation direction of the linear sensor 14 and the motion stage 12 caused by mechanical error, thereby avoiding its impact on the accuracy of subsequent wafer positioning.

[0130] Furthermore, those skilled in the art have measured the wafer positioning accuracy without the aforementioned correction steps, and the error is within 100 μm. After correction by the wafer positioning method provided in the first aspect of the present invention, the wafer positioning error can be controlled within 8 μm, greatly improving the accuracy of wafer positioning.

[0131] In summary, the wafer positioning method, wafer positioning system, chemical mechanical polishing equipment, and computer-readable storage medium provided by the present invention can all determine the offset and first deflection angle of the wafer relative to the motion stage based on multiple marks on a standard wafer. They can also determine the second deflection angle of the linear sensor 14 and the motion stage 12 in a preset translation direction, thereby more efficiently and accurately compensating for the coordinates of the measurement point in the motion stage coordinate system, so as to improve the efficiency of wafer measurement and the accuracy of wafer positioning.

[0132] Although the methods described above are illustrated and depicted as a series of actions for the sake of simplicity, it should be understood and appreciated that these methods are not limited by the order of the actions, as some actions may occur in a different order and / or concurrently with other actions from the illustrations and descriptions herein or not illustrated and described herein but which may be understood by those skilled in the art, according to one or more embodiments.

[0133] Those skilled in the art will understand that information, signals, and data can be represented using any of a variety of different techniques and arts. For example, the data, instructions, commands, information, signals, bits, symbols, and chips described throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or optical particles, or any combination thereof.

[0134] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps are described above in a generalized manner in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in different ways for each specific application, but such implementation decisions should not be construed as departing from the scope of the invention.

[0135] The various illustrative logic modules and circuits described in conjunction with the embodiments disclosed herein may be implemented or performed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but in alternatives, it may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0136] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of both. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor such that the processor can read and write information to / from the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and storage medium may reside as discrete components in the user terminal.

[0137] In one or more exemplary embodiments, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functionality may be stored or transmitted as one or more instructions or code on or through a computer-readable medium. A computer-readable medium includes both computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. A storage medium may be any available medium accessible to a computer. By way of example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and is accessible to a computer. Any connection is also legitimately referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. As used in this article, disk and disc include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and Blu-ray discs. Disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Combinations of these should also be included within the scope of computer-readable media.

[0138] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A chemical mechanical grinding apparatus, characterized in that, include: A grinding mechanism is used to perform chemical mechanical polishing on wafers to be processed; A film thickness measurement machine is used to determine the film thickness at multiple measurement points on the surface of the wafer; as well as A wafer positioning system is used to determine the true coordinates of each measurement point to cooperate with the film thickness measurement instrument to characterize the polishing thickness and / or polishing flatness of the chemical mechanical polishing process, wherein the wafer positioning system is configured as follows: The wafer to be positioned is placed on a motion stage and the motion stage is rotated to collect distance data from multiple positions on the edge of the wafer to the center of rotation of the motion stage via a linear sensor. The distance data from the multiple positions to the rotation center of the motion table is analyzed to extract the edge region data and the gap region data. According to the edge region data, an offset of a centroid of the wafer relative to a rotation center of the motion table is determined ; parsing the gap region data to determine a center point coordinate thereof and combining the offset to determine a first deflection angle of a gap orientation of the wafer with respect to a preset translation direction of the motion stage ; According to the offset The first deflection angle And the second deflection angle between the linear sensor and the preset translation direction of the motion table. Determine the corresponding positioning compensation amount ;as well as Using the positioning compensation amount The compensation measurement point is located in the measurement coordinates of the motion table coordinate system. To determine the true coordinates of the measurement point in the coordinate system of the motion table. .

2. The chemical mechanical polishing apparatus of claim 1, wherein Before collecting distance data from multiple locations on the wafer edge to the rotation center of the motion stage, the wafer positioning system is further configured as follows: A standard wafer is adsorbed onto the motion stage, wherein a first mark is located at the center of the detection surface of the standard wafer; The motion stage is moved to move the center of the first mark to the rotation center of the motion stage, and the motion stage is rotated to acquire induced voltages at multiple locations on the edge of the standard wafer via the linear sensor; and Based on the distance from the edge region of the standard wafer to its centroid. and the average value of the induced voltage at each of the said locations in the edge region when the linear sensor acquires the data. The correspondence between the induced voltage and the distance is calibrated.

3. The chemical mechanical polishing apparatus of claim 2, wherein the polishing pad is a porous pad. The step of moving the motion table to move the center of the first mark to the rotation center of the motion table includes: The motion stage is initially moved to move the first marker into the field of view of a camera, and the motion stage is rotated by a preset first step length to acquire multiple calibration images via the camera. parsing each of the calibration images to determine a center coordinate of a center of the first marker in the corresponding calibration image ; fitting each of the center coordinates to determine a rotation center coordinate of the rotation center of the motion stage in a camera coordinate system; and Based on the rotation center coordinates, the motion table is moved again to move the center of the first mark to the rotation center of the motion table.

4. The chemical mechanical grinding apparatus as described in claim 3, characterized in that, The first step is no longer than The number of calibration images collected shall not be less than Aspect, the pair of the center coordinates The steps of fitting the data to determine the rotation center coordinates of the motion stage in the camera coordinate system include: Construct a system of least squares fitting equations for the coordinates of the rotation center: wherein, and an offset amount indicating the rotation center coordinate, a radius of a circle corresponding to the rotation center coordinate; and The center coordinates of the first mark in each calibration image. Substituting these equations into the least squares fitting system, the coordinates of the rotation center of the motion platform in the camera coordinate system are determined. .

5. The chemical mechanical polishing apparatus of claim 2, wherein the polishing pad is a porous pad. The step of rotating the motion stage to collect distance data from multiple locations on the edge of the wafer to the center of rotation of the motion stage includes: The motion stage is rotated by a preset second step size to obtain data from the wafer edge collected by the linear sensor. The induced voltage at each position, wherein the second step size is no greater than 0.2°. Natural numbers not less than 1800; and The linear sensor collects the induced voltage at each of the stated positions on the wafer edge, and substitutes these induced voltages into the correspondence between the distance and the induced voltage to determine the distance data from each of the stated positions on the wafer edge to the rotation center of the motion stage.

6. The chemical mechanical grinding apparatus as described in claim 5, characterized in that, The linear sensor has a length along the radial direction of the wafer of [missing information]. The step of determining the distance data from each position on the wafer edge to the rotation center of the motion stage by substituting the induced voltage collected by the linear sensor at each of the aforementioned positions on the wafer edge into the correspondence between the induced voltage and the distance includes: The induced voltage obtained by the linear sensor at each of the aforementioned locations on the edge of the wafer. Determine the minimum value among them. and maximum value ;as well as Each of the induced voltages Substitute them into the following conversion formulas respectively: to determine distances of the positions of the wafer edge to the rotation center of the motion stage .

7. The chemical mechanical polishing apparatus of claim 1, wherein the polishing pad is a porous pad. The step of parsing the distance data from the multiple positions to the rotation center of the motion table to extract edge region data and gap region data includes: The distance from multiple locations on the edge of the wafer to the center of rotation of the motion stage Perform difference operations on adjacent positions to determine a difference array. ,in, ; A dividing threshold is determined based on the standard deviation of each element in the difference array; The difference array is traversed to determine the start and end points of the notch region at the edge of the wafer based on the division threshold; Based on the distances from the starting point, the ending point, and each position in between to the rotation center of the motion platform. Determine the data for the gap region; and determining the edge region data based on distances from each position other than the gap region to a center of rotation of the motion stage and ​ 8. The chemical mechanical polishing apparatus of claim 7 wherein the polishing pad is a continuous pad. The step of traversing the difference array to determine the start and end points of the notch region at the wafer edge based on the partitioning threshold includes: Iterate through the difference array and compare the value of each element with the dividing threshold. Responding to the value of any of the elements If the value of an element is greater than the threshold, and the values ​​of the preceding preset number of elements are all less than the threshold, then the position corresponding to that element is determined as the starting point of the gap region; and Responding to the value of any of the elements If the value of an element is greater than the threshold, and the value of a predetermined number of subsequent elements is less than the threshold, the position corresponding to that element is determined as the end point of the gap region.

9. The chemical mechanical grinding apparatus as described in claim 7, characterized in that, The data of the gap region is analyzed to determine its center point coordinates. The steps include: Based on the distance from each of the positions in the edge region to the rotation center of the motion table And the corresponding rotation angle of the motion table, to determine the X-axis projection of each position in the edge region onto the motion table coordinate system. and Y-axis projection ; According to the X-axis projection Construct an array of independent variables and based on the Y-axis projection. Construct an array of dependent variables to generate the following system of linear equations: in, The amount of data in the edge region. and Let be the power of the independent variable in the system of linear equations. and The elements are the coefficient matrix of the linear equation system; and The linear equations are solved using Gaussian elimination to calculate the parameters of the corresponding quadratic fitting curve. The coordinates of the center point of the notch region are then determined based on the minimum value of the quadratic fitting curve. .

10. The chemical mechanical grinding apparatus as described in claim 1, characterized in that, determining, according to the edge region data, an offset amount of a centroid of the wafer relative to a rotation center of the motion stage comprises: Three locations are randomly selected from the edge region data, and the center coordinates of the circle formed by these three locations in the motion table coordinate system are determined based on their distances from the rotation center of the motion table and the corresponding rotation angle of the motion table. ;as well as With the coordinates of the center of the circle Initial position parameters An iterative optimization function for the LM algorithm is constructed, and the optimal solution for the iterative optimization is calculated based on the chi-square values ​​of the center coordinates before and after the iterative optimization, in order to determine the offset of the centroid of the wafer relative to the rotation center of the motion stage. .

11. The chemical mechanical grinding apparatus as described in claim 10, characterized in that, The iterative optimization function is expressed as: in, and They are the first Second and third The position parameters obtained in the next iteration It is the Jacobian matrix formed by calculating the partial derivatives of the residual values ​​with respect to the position parameters. It is the damping coefficient that adjusts the iteration speed. It is the identity matrix. The formula for calculating the chi-square value is: in, The chi-square value is... The linear sensor acquires the number of positions at the edge of the wafer. For natural numbers, Position parameters The coordinate representation, Position parameters The radius is represented by .

12. The chemical mechanical grinding apparatus as described in claim 11, characterized in that, The optimal solution for iterative optimization is calculated based on the chi-square values ​​of the center coordinates before and after iterative optimization, in order to determine the offset of the centroid of the wafer relative to the rotation center of the motion stage. The steps include: The chi-square value after this iteration Chi-square value after the previous iteration Compare; The chi-square value after this iteration Less than the chi-square value after the previous iteration The damping coefficient is then reduced for the next round of iterative optimization. The chi-square value after this iteration Greater than or equal to the chi-square value after the previous iteration Increase the damping coefficient to perform the next round of iterative optimization; and The chi-square value after this iteration If the value is less than the preset chi-square threshold, the position parameters obtained from this iteration are used. Determine the offset of the centroid of the wafer relative to the rotation center of the motion stage. .

13. The chemical mechanical grinding apparatus as described in claim 3, characterized in that, A second mark is also formed on the edge of the standard wafer. The second mark is located on the extension line connecting the center of the notch on the standard wafer and the first mark. Before collecting distance data from multiple locations on the edge of the wafer to the rotation center of the motion stage, the wafer positioning system is further configured as follows: After moving the center of the first marker to the rotation center of the motion stage, the motion stage is rotated for the first time to move the second marker to the center of the camera's field of view, and the rotation angle of the motion stage at this time is recorded. ; The motion stage is rotated again to collect distance data from multiple locations on the edge of the standard wafer to the rotation center of the motion stage via the linear sensor, and the distance data is analyzed to determine the deflection angle of the notch orientation of the standard wafer relative to the preset translation direction of the motion stage. ; as well as According to the rotation angle and the aforementioned deflection angle Determine the second deflection angle between the linear sensor and the preset translation direction of the motion table. .

14. The chemical mechanical grinding apparatus as described in claim 1, characterized in that, First deflection angle It is represented as: The positioning compensation amount It is represented as: The actual coordinates It is represented as: 。 15. A method for characterizing a chemical mechanical grinding process, characterized in that, Includes the following steps: A chemical mechanical polishing process is performed on the wafer to be processed via the polishing mechanism of the chemical mechanical polishing apparatus according to any one of claims 1 to 14; The wafer positioning system of the chemical mechanical polishing equipment determines the true coordinates of multiple measurement points on the surface of the wafer to be processed. as well as The film thickness at multiple measurement points on the wafer surface is determined using the film thickness measurement machine of the chemical mechanical polishing equipment, based on the true coordinates of the multiple measurement points, in order to characterize the polishing thickness and / or polishing flatness of the chemical mechanical polishing process.

16. A computer-readable storage medium storing computer instructions thereon, characterized in that, When the computer instructions are executed by the processor, the characterization method of the chemical mechanical polishing process as described in claim 15 is implemented.

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