Spiral three-dimensional surface topography measurement method and device

Abstract

The present invention discloses a spiral three-dimensional surface topography measurement method and device, the spiral three-dimensional surface topography measurement method comprises the following steps: driving the measured object to rotate at a constant speed around the θ axis, and driving the measuring probe to move continuously along the Y axis direction from the center to the edge of the measured object, wherein the moving speed of the measuring probe along the Y axis direction is different in different sections; collecting the relative height value of the measured object surface by the measuring probe to obtain a cylindrical coordinate system data set of the upper surface of the measured object; converting the obtained cylindrical coordinate system data set into a spatial rectangular coordinate system data set to obtain the topography data of the upper surface of the measured object in three-dimensional space. The above-mentioned spiral three-dimensional surface topography measurement method can improve the measurement efficiency while ensuring the measurement accuracy, reduce the amount of unnecessary data collection, thereby optimizing the overall measurement process, shortening the measurement time and reducing the complexity of data processing.

Description

Technical Field

[0001] The invention relates to the field of measurement technology, and in particular to a spiral three-dimensional surface topography measurement method and device. Background Art

[0002] Three-dimensional morphology information is gaining increasing attention because it can more comprehensively and truly reflect the characteristics of the part surface and effectively evaluate the surface processing quality. By measuring the three-dimensional morphology, the surface quality of the part can be comprehensively evaluated, thereby verifying the advantages and disadvantages of the processing method and the rationality of the design requirements, and then guiding the optimization of the processing technology to achieve high-quality part surfaces and ensure their functional use.

[0003] Existing three-dimensional topography measurement methods usually use a measuring probe to collect three-dimensional topography data corresponding to different rotation radii of the object to be measured. Common scanning methods include concentric circle scanning and spiral scanning. Compared with concentric circle scanning, spiral scanning has significantly improved efficiency. However, during the spiral scanning measurement process, the Y-axis that drives the measurement probe to move and the θ-axis that drives the object to be measured to rotate both move at a uniform speed. Although this method is convenient for calculating the coordinates of each measurement point, it has certain disadvantages: the measurement radius interval of each circle of data is fixed (Y-axis uniform speed). When the measurement radius interval is large, the measurement efficiency is high but the data density is low, and it is difficult to reflect more details of the wafer surface morphology; when the measurement radius interval is small, although the data density is high, the measurement efficiency is relatively low. Summary of the invention

[0004] The technical problem of the present invention is to provide a spiral three-dimensional surface topography measurement method and device that can take into account both measurement efficiency and data density, so as to achieve more accurate and efficient topography measurement of the surface of an object.

[0005] A spiral three-dimensional surface topography measurement method comprises the following steps:

[0006] The object to be measured is driven to rotate at a constant speed around the θ axis, and at the same time, the measuring probe is driven to move continuously along the Y axis from the center to the edge of the object to be measured to form a spiral scanning path, wherein the moving speed of the measuring probe along the Y axis is different in different sections;

[0007] The relative height value of the surface of the measured object is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the measured object;

[0008] The obtained cylindrical coordinate system data set (r, θ, z) is converted into a spatial rectangular coordinate system data set (x, y, z) to obtain the topographic data of the upper surface of the measured object in three-dimensional space.

[0009] In one embodiment, the moving speed of the measuring probe along the Y-axis direction is different in different sections, including: moving at a higher speed in the area of ​​the Y-axis close to the center of the measured object, and moving at a lower speed in the area of ​​the Y-axis close to the edge of the measured object.

[0010] In one embodiment, the different sections in the Y-axis direction include three stages: R A Duan, R D Duan and R B segment, where R A The segment is the initial stage when the measuring probe moves from the center to the edge of the object being measured, and the speed is V y1 ; R D The first stage is the stage of gradual speed reduction, and the measuring probe is from the speed V y1 Decelerate to speed V y2 ; R B The segment is the area close to the edge of the object being measured. The measuring probe moves at a speed of V y2 Move at a constant speed.

[0011] In one embodiment, the object to be measured is a wafer, and its edge has a straight positioning edge. When the Y-axis direction coincides with the perpendicular midline of the positioning edge, R A The segment extends from the center of the wafer to the position close to the positioning edge, R D Segment from R A The segment starts at the end point and extends to the positioning edge, R B Segment from R D The segment begins at the end point and continues to the circumference where the edge of the wafer is located.

[0012] In one embodiment, V y2 V y1 0.1 to 0.5 times.

[0013] In one embodiment, in R A During the measurement, the relative height value of the surface of the object to be measured is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the object to be measured, including the following steps:

[0014] When the measuring probe moves to the center of the wafer, record the θ-axis rotation angle θ at this time. S ;

[0015] The rotation angle θ1 of the first valid acquisition point is calculated by the following formula:

[0016]

[0017] Among them, “|” is the integer division symbol, and i is the angle interval between two adjacent acquisition points;

[0018] The distance Y1 from the center of the circle in the Y-axis direction, i.e. the rotation radius, is calculated using the following formula:

[0019]

[0020] Among them, V θ is the rotation speed of the θ axis, V y1 To measure the moving speed of the probe;

[0021] The rotation radius Y of the nth measuring point in the Y-axis direction is calculated by the following formula: n :

[0022]

[0023] Where t is the time interval between two collection points;

[0024] The rotation angle of the nth measurement point is calculated by the following formula:

[0025]

[0026] By using the rotation radius r and rotation angle θ of all measurement points, plus the relative height value z measured by the measurement probe, a data set (r, θ, z) of the cylindrical coordinate system of the upper surface of the wafer can be obtained.

[0027] In one embodiment, in R D During the measurement, the relative height value of the surface of the object to be measured is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the object to be measured, including the following steps:

[0028] The R is calculated by the following formula A The last valid acquisition point N of the segment:

[0029]

[0030] Where L is R A Segment and R D The total length of the segment, R D For R D The length of the segment, “|” means it is divisible;

[0031] The R is calculated by the following formula A The rotation radius Y of the last valid acquisition point N in the segment N :

[0032]

[0033] During the deceleration process, the rotation radius Y of each acquisition point d Calculated by the following formula:

[0034]

[0035] Where D is the deceleration of the Y axis, and d is the number of the acquisition point;

[0036] The rotation radius Y of the last acquisition point in the deceleration phase K Calculated by the following formula:

[0037]

[0038] Among them, k is the total number of collection points in the deceleration stage, ， T is the deceleration time of the Y axis;

[0039] The rotation angle of the nth measurement point is calculated by the following formula:

[0040]

[0041] By using the rotation radius r and rotation angle θ of all measurement points, plus the relative height value z measured by the measurement probe, a data set (r, θ, z) of the cylindrical coordinate system of the upper surface of the wafer can be obtained.

[0042] In one embodiment, in R B During the measurement, the relative height value of the surface of the object to be measured is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the object to be measured, including the following steps:

[0043] The rotation radius Y of the last acquisition point in the deceleration stage K Then to R B The deceleration distance Y before the start of the segment D Calculated by the following formula:

[0044]

[0045] R B The distance Y that moves uniformly before the first uniform motion collection point M in the segment m Calculated by the following formula:

[0046]

[0047] The R is calculated by the following formula B The rotation radius Y of the first uniform motion acquisition point M in the segment M :

[0048]

[0049] The R is calculated by the following formula B The rotation radius Y of any collection point p after the first uniform motion collection point M in the segment p:

[0050]

[0051] The rotation angle of the nth measurement point is calculated by the following formula:

[0052]

[0053] By using the rotation radius r and rotation angle θ of all measurement points, plus the relative height value z measured by the measurement probe, a data set (r, θ, z) of the cylindrical coordinate system of the upper surface of the wafer can be obtained.

[0054] In one embodiment, the method of driving the measured object to rotate at a constant speed around the θ axis and driving the measuring probe to move continuously along the Y axis to form a spiral scanning path includes the following steps:

[0055] The object to be measured is driven to rotate at a constant speed around the θ axis, and the relative height value of the surface of the object to be measured is collected by the measuring probe at the same time;

[0056] When the measured object reaches a uniform rotation, the measuring probe is driven to move from a position on the other side of the measured object's center that is opposite to the moving direction, to ensure that the moving speed of the measuring probe reaches a uniform speed when it reaches the measured object's center.

[0057] A spiral three-dimensional surface topography measuring device, comprising:

[0058] A rotation drive assembly, used to drive the object to be measured to rotate at a constant speed around the θ axis;

[0059] The Y-axis driving component is used to drive the measuring probe to move continuously along the Y-axis direction to form a spiral scanning path, and the moving speed of the measuring probe along the Y-axis direction is different in different sections;

[0060] The measuring probe is used to collect the relative height value of the surface of the measured object along the Y-axis direction while the measured object rotates around the θ-axis;

[0061] The data acquisition module is used to obtain the cylindrical coordinate system data set (𝑟,𝜃,𝑧) of the surface of the measured object collected by the measuring probe;

[0062] A data processing module is used to convert the obtained cylindrical coordinate system data set (𝑟,𝜃,𝑧) into a spatial rectangular coordinate system data set (x,y,z);

[0063] The controller is used to control the movement of the rotation drive assembly, the Y-axis drive assembly and the measuring probe, so that the object to be measured can rotate at a uniform speed and the measuring probe can move at different speeds in different sections in the Y-axis direction.

[0064] The spiral three-dimensional surface topography measurement method and device adjusts the moving speed of the measuring probe according to the changes in the surface topography of the measured object, adopts a lower acquisition density in areas with small topography changes, and increases the acquisition density in areas with drastic topography changes. This method can improve measurement efficiency while ensuring measurement accuracy, reduce unnecessary data collection, thereby optimizing the overall measurement process, shortening measurement time and reducing the complexity of data processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 is a schematic structural diagram of a spiral three-dimensional surface topography measuring device in one embodiment of the present invention;

[0066] Figure 2 is a flow chart of a spiral three-dimensional surface topography measurement method in one embodiment of the present invention;

[0067] Figure 3 Schematic diagram of different measurement radii of wafer;

[0068] Figure 4 It is a schematic diagram of Y-axis speed and movement distance;

[0069] Figure 5 It is a schematic diagram of the distribution of the sampling points during the deceleration of the Y axis;

[0070] Figure 6 Schematic diagram of spiral measurement of non-uniform density.

[0071] Explanation of reference numerals: 1. platform; 2. rotating table; 3. carrier plate; 4. Y-axis drive assembly; 5. bracket assembly; 6. measuring probe. DETAILED DESCRIPTION

[0072] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the specific implementation methods of the present invention are described clearly and completely below in conjunction with the accompanying drawings. Obviously, the specific details described below are only part of the embodiments of the present invention, and the present invention can also be implemented in many other embodiments different from those described herein. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0073] In this document, when an element is referred to as being "fixed to" 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 at the same time. The directional words such as front, back, top, and bottom involved are defined by the positions of the parts in the drawings and the positions of the parts relative to each other, just for the clarity and convenience of expressing the technical solution. It should be understood that the use of the directional words should not limit the scope of protection claimed in the present invention.

[0074] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0075] The spiral three-dimensional surface morphology measurement method and device of the present application are used to measure the three-dimensional surface morphology of the measured object. The measured object refers to the object that needs to be measured, such as wafers, silicon wafers used in the photovoltaic industry, and other parts with flat surfaces.

[0076] like Figure 1 As shown, the present application provides a three-dimensional surface topography measuring device, including a rotation drive component, a Y-axis drive component 4, a measuring probe 6, a data acquisition module, a data processing module and a controller, and the rotation drive component is used to drive the measured object to rotate around the θ axis at a uniform speed. In this embodiment, the rotation drive component includes a rotating table 2 and a carrier 3, the rotating table 2 is arranged on the platform 1, the carrier 3 is placed on the rotating table 2, and the measured object is placed on the carrier 3 during measurement. The Y-axis drive component 4 is used to drive the measuring probe 6 to move continuously along the Y-axis direction to form a spiral scanning path, and the moving speed of the measuring probe 6 along the Y-axis direction is different in different sections. In this embodiment, the Y-axis drive component is installed on the platform 1 through the bracket component 5, and the Y-axis drive component can use a linear module or a high-precision screw module. The data acquisition module is used to obtain a cylindrical coordinate system data set (𝑟,𝜃,𝑧) of the surface of the measured object collected by the measuring probe 6. The data processing module is used to convert the obtained cylindrical coordinate system data set (𝑟, 𝜃, 𝑧) into a spatial rectangular coordinate system data set (x, y, z); the controller is used to control the movement of the rotation drive assembly, the Y-axis drive assembly 4 and the measuring probe 6, so that the object to be measured rotates at a uniform speed, and the measuring probe 6 moves at different speeds in different sections in the Y-axis direction.

[0077] See also Figure 2 The spiral three-dimensional surface topography measurement method in one embodiment of the present invention comprises the following steps:

[0078] Step S1: driving the object to be measured to rotate at a constant speed around the θ axis, and driving the measuring probe to move continuously along the Y axis from the center to the edge of the object to be measured to form a spiral scanning path, wherein the moving speed of the measuring probe along the Y axis is different in different sections.

[0079] Step S2: collecting the relative height value of the surface of the measured object through the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the measured object;

[0080] Step S3: Convert the obtained cylindrical coordinate system data set (r, θ, z) into a spatial rectangular coordinate system data set (x, y, z) to obtain the topographic data of the upper surface of the measured object in three-dimensional space.

[0081] The above-mentioned spiral 3D surface topography measurement method adjusts the moving speed of the measuring probe according to the changes in the surface topography of the measured object, adopts a lower acquisition density in areas with small topography changes, and increases the acquisition density in areas with drastic topography changes. This method can improve measurement efficiency while ensuring measurement accuracy, reduce unnecessary data collection, thereby optimizing the overall measurement process, shortening measurement time and reducing the complexity of data processing.

[0082] The spiral three-dimensional surface topography measurement method of the present application is described in detail below using a wafer as an example. Considering the surface characteristics of the wafer, the topography of the middle part of the wafer surface changes less and can be measured with a smaller density, while the topography of the edge of the wafer surface changes dramatically and should be measured with a larger density. The edge of the wafer has a straight positioning edge (such as Figure 3 As shown in FIG. 1 ), the present application divides the radius R of the wafer perpendicular to the positioning edge at the positioning edge into three parts: R A Duan, R D Duan and R B Duan, R. A The segment extends from the center of the wafer to the position close to the positioning edge, R D Segment from R A The segment starts at the end point and extends to the positioning edge, R B Segment from R D The Y axis is measured at the R in the middle of the wafer. A The segment interval is V y1 The speed is uniform, the scanning circle interval is I1, and the R between the middle and edge of the wafer D The Y axis decelerates in the interval, from the speed V y1 Decelerate to V y2 ; R at the edge of the wafer B The Y axis of the interval is V y2 The speed is uniform and the scanning circle interval is I2.

[0083] The following are known quantities:

[0084] I1: The scanning circle interval of the Y axis in the middle part of the wafer;

[0085] I2: The scanning circle interval of the Y axis at the edge of the wafer;

[0086] V θ : θ-axis movement speed;

[0087] L: The distance between the wafer positioning edge and the center of the circle;

[0088] D: Y-axis deceleration, a negative number;

[0089] i: the θ-axis rotation angle interval between two acquisition points;

[0090] r1: The distance from the first valid acquisition point to the center of the circle in the Y-axis direction, i.e. the rotation radius;

[0091] θ1: The θ-axis angle of the first valid acquisition point;

[0092] The following is the calculation amount:

[0093] V y1 : Y axis in the middle of the wafer R A The speed of the interval, ;

[0094] V y2 : Y axis at the edge of the wafer R B The speed of the interval, , V y2 Less than V y1 In one embodiment, V y2 V y1 Specifically, V y2 = 0.3V y1 ;

[0095] T: Y-axis deceleration time,

[0096] R D : Y-axis deceleration distance. From the acceleration distance formula, we can get: ;

[0097] t: The interval between every two acquisition points, the θ axis rotates at a constant speed, .

[0098] 1. R A Measurement of segment areas

[0099] In R ADuring the measurement, the relative height value of the surface of the object to be measured is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the object to be measured, including the following steps:

[0100] S1-1: Drive the object to be measured (wafer) to rotate at a constant speed around the θ axis, and collect the relative height value of the surface of the object to be measured through the measuring probe. Specifically, at the beginning of the measurement, the control system controls the rotation stage 2 to start, so that the object to be measured rotates at a constant speed around the θ axis at its center. This rotation is to ensure that the surface of the object to be measured can be evenly covered in the spiral scanning path.

[0101] S1-2: When the object to be measured reaches a uniform rotation, the measuring probe is driven to move from the position on the other side of the center of the circle opposite to the moving direction. This ensures that the rotation of the object to be measured and the movement of the measuring probe are both in a uniform state when the measuring probe passes through the center of the circle.

[0102] S1-3: When the measuring probe moves to the center of the wafer, the position latch function is triggered and the θ-axis rotation angle θ at this time is recorded. S . This is the base angle for subsequent data processing.

[0103] S1-4: Calculate the rotation angle θ1 of the first valid acquisition point using the following formula:

[0104]

[0105] Among them, “|” is the integer division symbol, and i is the angle interval between two adjacent acquisition points.

[0106] This step ensures that the rotation angle of the first valid acquisition point is aligned with the set angle interval i to ensure the consistency of the angle intervals between subsequent acquisition points.

[0107] S1-4: Calculate the rotation radius Y1 of the first valid acquisition point by the following formula:

[0108]

[0109] Among them, V θ is the rotation speed of the θ axis, V y1 To measure the moving speed of the probe.

[0110] This formula relates the rotation angle to the speed at which the probe is moving and calculates the exact position of the probe on the Y axis.

[0111] S1-5: Calculate the position Y of the nth measurement point in the Y-axis direction by the following formula n :

[0112]

[0113] Where t is the time interval between two acquisition points.

[0114] S1-6: Calculate the rotation angle of the nth measurement point using the following formula:

[0115]

[0116] By adding the rotation radius r and rotation angle θ of all measuring points and the relative height value z measured by the measuring probe, R can be obtained. A The data set (r,θ,z) of the cylindrical coordinate system of the wafer surface in the segment area.

[0117] (ii) R D Segment area measurement

[0118] When the measuring probe enters R D In the segment, the moving speed in the Y-axis direction changes from V y1 Gradually reduce the speed to the target speed V at a fixed deceleration rate D y2 During this process, the measuring probe will continue to move along the Y axis, while the object being measured will rotate at a constant speed around the θ axis, and the probe will continue to collect the relative height value of the surface of the object being measured.

[0119] In R D During the measurement, the relative height value of the surface of the object to be measured is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the object to be measured, including the following steps:

[0120] S2-1: Calculate R A The rotation radius Y of the last valid acquisition point N in the segment N

[0121] Since the interval between every two acquisition points is the same rotation angle, when the θ axis rotates at a constant speed, the interval between every two acquisition points is also the same. The measurement time can be calculated by the number of acquisition points, thereby calculating the time point of Y axis deceleration, and it is also convenient to calculate the Y axis position of each acquisition point. The time point when the Y axis starts to decelerate can be converted to a certain acquisition point N points after the first formal acquisition point mentioned above. When collecting N points, the motion controller simultaneously controls the Y axis drive component 4 to decelerate, that is, when the θ axis rotates to the angle of point N, the Y axis drive component 4 is controlled to start decelerating at a deceleration rate D.

[0122] In order to make the Y axis complete deceleration when it reaches the positioning edge, that is, ,therefore .

[0123] As mentioned above, the Y-axis position Y1, the θ-axis angle θ1, and the Y-axis at R A The stage is uniform motion, so we can get , “|” means integer division,

[0124] Therefore, R can be calculated by the following formula A The rotation radius Y of the last valid acquisition point N in the segment N :

[0125]

[0126] Among them, Y1 is R A The rotation radius of the first acquisition point of the segment, t is the time interval between two acquisition points, and N is R A The last valid acquisition point number of the segment. This formula is used to calculate the starting acquisition point position in the deceleration phase, and deceleration starts from this point.

[0127] S2-2: During deceleration, the rotation radius Y of each acquisition point d Calculated by the following formula:

[0128]

[0129] Among them, V y1 is the initial speed before deceleration, D is the deceleration in the Y-axis direction, and d is the acquisition point number.

[0130] S2-3: The rotation radius Y of the last acquisition point in the deceleration phase K Calculated by the following formula:

[0131]

[0132] Among them, k is the total number of collection points in the deceleration stage, ， “|” is the integer division symbol ， T is the Y-axis deceleration time.

[0133] S2-4: Calculate the rotation angle of the nth measurement point using the following formula:

[0134]

[0135] S2-5: By using the rotation radius r and rotation angle θ of all measurement points, plus the relative height value z measured by the measurement probe, a data set (r, θ, z) of the cylindrical coordinate system of the upper surface of the wafer can be obtained.

[0136] (III) R B Segment area measurement

[0137] R B The segment is immediately followed by R D The uniform motion phase after the deceleration phase. B During the period, the measuring probe is already at R DThe segment completes the deceleration motion, and the Y-axis position Y of the last acquisition point K has been calculated. At this time, the probe moves from Y K Continue moving forward and at R B The speed V y2 Uniform motion.

[0138] In R B During the measurement, the relative height value of the surface of the object to be measured is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the object to be measured, including the following steps:

[0139] S3-1: The last acquisition point in the deceleration phase is from point K to point R B The deceleration distance Y before the start of the segment D Calculated by the following formula:

[0140]

[0141] Among them, Y N is the rotation radius of the last valid acquisition point of the RA segment, V y1 YesR D The initial speed of the segment, T is the deceleration time, D is the deceleration, Y K is the rotation radius of the last acquisition point in the deceleration phase.

[0142] S3-2: R B The distance Y that moves uniformly before the first uniform motion collection point M in the segment m Calculated by the following formula:

[0143]

[0144] Among them, t is the time interval of the collection points, T is the deceleration time, k is the total number of collection points in the deceleration stage, V y2 For R B The uniform motion speed of the segment.

[0145] S3-3: Determine the value of R by the following formula B The rotation radius Y of the first uniform motion acquisition point M in the segment M :

[0146]

[0147] This formula converts the position Y of the last acquisition point in the deceleration stage K , the total distance of deceleration movement Y D and the initial distance Y before uniform motion m Added together, it is determined to enter R B The first acquisition point position after the segment.

[0148] S3-4: Calculate the R B The rotation radius Y of any collection point p after the first uniform motion collection point M in the segment p :

[0149]

[0150] S3-5: Calculate the rotation angle of the nth measurement point using the following formula:

[0151]

[0152] S3-6: By using the rotation radius r and rotation angle θ of all measurement points, plus the relative height value z measured by the measurement probe, a data set (r, θ, z) of the cylindrical coordinate system of the upper surface of the wafer can be obtained.

[0153] The Y-axis position r, θ-axis angle θ and relative height z collected by the sensor of each valid collection point are spliced ​​together to obtain the data set (r, θ, z).

[0154] Based on the obtained three-dimensional shape data of the upper surface of the measured object, the cylindrical coordinate system is converted into a spatial rectangular coordinate system to obtain the final three-dimensional shape information (x, y, z) of the surface of the measured object.

[0155] Specifically, coordinate transformation is performed by the following formula:

[0156] x = cosθ × r

[0157] y = sinθ × r

[0158] The spiral three-dimensional surface topography measurement method and device adjusts the moving speed of the measuring probe according to the changes in the surface topography of the measured object, adopts a lower acquisition density in areas with small topography changes, and increases the acquisition density in areas with drastic topography changes. This method can improve measurement efficiency while ensuring measurement accuracy, reduce unnecessary data collection, thereby optimizing the overall measurement process, shortening measurement time and reducing the complexity of data processing.

[0159] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A spiral three-dimensional surface topography measurement method, characterized in that: The following steps are involved: The object to be measured is driven to rotate at a constant speed around the θ axis, and the measuring probe is driven to move continuously along the Y axis from the center to the edge of the object to be measured to form a spiral scanning path, wherein the moving speed of the measuring probe along the Y axis is different in different sections, the θ axis is the rotation axis, and the Y axis is the translation axis; The relative height value of the surface of the measured object is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the measured object; The obtained cylindrical coordinate system data set (r, θ, z) is converted into a spatial rectangular coordinate system data set (x, y, z) to obtain the topographic data of the upper surface of the measured object in three-dimensional space; The moving speed of the measuring probe along the Y-axis direction is different in different sections, including: moving at a higher speed in the area of ​​the Y-axis close to the center of the measured object, and moving at a lower speed in the area of ​​the Y-axis close to the edge of the measured object; The different sections in the Y-axis direction include three stages: R A Duan, R D Duan and R B segment, where R A The segment is the initial stage when the measuring probe moves from the center to the edge of the object being measured, and the speed is V y1 ; R D The first stage is the stage of gradual speed reduction, and the measuring probe is from the speed V y1 Decelerate to speed V y2 ; R B The segment is the area close to the edge of the object being measured. The measuring probe moves at a speed of V y2 Move at a constant speed; In R A During the measurement, the relative height value of the surface of the object to be measured is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the object to be measured, including the following steps: When the measuring probe moves to the center of the wafer, record the θ-axis rotation angle θ at this time. S ; The rotation angle θ1 of the first valid acquisition point is calculated by the following formula: θ1=(θ S |i)×i+i Where "|" is the integer division symbol, and i is the angle interval between two adjacent acquisition points; The distance Y1 from the center of the circle in the Y-axis direction, i.e. the rotation radius, is calculated using the following formula: Among them, V θ is the rotation speed of the θ axis, V y1 To measure the moving speed of the probe; The rotation radius Y of the nth measuring point in the Y-axis direction is calculated by the following formula: n : Y n =Y1+V y1 ×t×(n-1) Where t is the time interval between two collection points; The rotation angle of the nth measurement point is calculated by the following formula: i n =θ1+i×(n-1) By using the rotation radius r and rotation angle θ of all measurement points, plus the relative height value z measured by the measurement probe, it is possible to obtain a data set (r, θ, z) of the cylindrical coordinate system of the upper surface of the wafer.

2. The spiral three-dimensional surface topography measurement method according to claim 1, characterized in that: The object to be measured is a wafer, and its edge has a straight positioning edge. When the Y-axis direction coincides with the perpendicular midline of the positioning edge, R A The segment extends from the center of the wafer to the position close to the positioning edge, R D Segment from R A The segment starts at the end point and extends to the positioning edge, R B Segment from R D The segment begins at the end point and continues to the circumference where the edge of the wafer is located.

3. The spiral three-dimensional surface topography measurement method according to claim 1, characterized in that: V y2 V y1 0.1 to 0.5 times.

4. The spiral three-dimensional surface topography measurement method according to claim 1, characterized in that: In R D During the measurement, the relative height value of the surface of the object to be measured is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the object to be measured, including the following steps: The R is calculated by the following formula A The last valid acquisition point N of the segment: N=(L-R D -Y1)÷V y1 |t Where L is R A Segment and R D The total length of the segment, R D For R D The length of the segment, "|" is divisible; The R is calculated by the following formula A The rotation radius Y of the last valid acquisition point N in the segment N : Y N =Y1+V y1 ×t×N During the deceleration process, the rotation radius Y of each acquisition point d Calculated by the following formula: Where D is the deceleration of the Y axis, and d is the number of the acquisition point; The rotation radius Y of the last acquisition point in the deceleration phase K Calculated by the following formula: Wherein, k is the total number of acquisition points in the deceleration stage, k = T|t, T is the deceleration time of the Y axis; The rotation angle of the nth measurement point is calculated by the following formula: i n =θ1+i×(n-1) By using the rotation radius r and rotation angle θ of all measurement points, plus the relative height value z measured by the measurement probe, it is possible to obtain a data set (r, θ, z) of the cylindrical coordinate system of the upper surface of the wafer.

5. The spiral three-dimensional surface topography measurement method according to claim 4, characterized in that: In R B During the measurement, the relative height value of the surface of the object to be measured is collected by the measuring probe to obtain a cylindrical coordinate system data set (r, θ, z) of the upper surface of the object to be measured, including the following steps: The rotation radius Y of the last acquisition point in the deceleration stage K Then to R B The deceleration distance Y before the start of the segment D Calculated by the following formula: R B The distance Y that moves uniformly before the first uniform motion collection point M in the segment m Calculated by the following formula: Y m =[t-(T-t×k)]×V y2 The R is calculated by the following formula B The rotation radius Y of the first uniform motion acquisition point M in the segment M : AND M =And K +Y D +Y m | The R is calculated by the following formula B The rotation radius Y of any collection point p after the first uniform motion collection point M in the segment p : AND p =And M +V y2 ×(t×p) The rotation angle of the nth measurement point is calculated by the following formula: i n =θ1+i×(n-1) By using the rotation radius r and rotation angle θ of all measurement points, plus the relative height value z measured by the measurement probe, it is possible to obtain a data set (r, θ, z) of the cylindrical coordinate system of the upper surface of the wafer.

6. The spiral three-dimensional surface topography measurement method according to claim 1, characterized in that: The method of driving the measured object to rotate at a constant speed around the θ axis and driving the measuring probe to move continuously along the Y axis to form a spiral scanning path includes the following steps: The object to be measured is driven to rotate at a constant speed around the θ axis, and the relative height value of the surface of the object to be measured is collected by the measuring probe at the same time; When the measured object reaches a uniform rotation, the measuring probe is driven to move from a position on the other side of the measured object's center that is opposite to the moving direction, to ensure that the moving speed of the measuring probe reaches a uniform speed when it reaches the measured object's center.

7. A measuring device for the spiral three-dimensional surface topography measuring method as claimed in claim 1, characterized in that: include: A rotation drive assembly, used to drive the object to be measured to rotate at a constant speed around the θ axis; A Y-axis driving component is used to drive the measuring probe to continuously move along the Y-axis direction to form a spiral scanning path, and the moving speed of the measuring probe along the Y-axis direction is different in different sections; The measuring probe is used to collect the relative height value of the surface of the measured object along the Y-axis direction while the measured object rotates around the θ-axis; A data acquisition module is used to obtain a cylindrical coordinate system data set (r, θ, z) of the surface of the measured object collected by the measuring probe; A data processing module is used to convert the obtained cylindrical coordinate system data set (r, θ, z) into a spatial rectangular coordinate system data set (x, y, z); The controller is used to control the movement of the rotation drive assembly, the Y-axis drive assembly and the measuring probe, so that the object to be measured rotates at a uniform speed and the measuring probe moves at different speeds in different sections in the Y-axis direction.

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