TWI846579B - Wafer positioning device and method - Google Patents

Abstract

A wafer positioning device, wherein the controller receives image data of the outer edge of the wafer, and calculates the precise position of the positioning feature of the outer edge of the wafer through the first-order derivative and the second-order derivative of the image data in combination with a polynomial regression operation, and after eliminating the positioning feature in the image data, calculates the center offset of the wafer based on the image data excluding the positioning feature, and then calculates the correction angle and the X-Y correction amount. The controller then controls the driving device to control the rotation of the rotating platform module according to the correction angle so that the positioning feature rotates to a specified angle, and controls the driving device of the wafer positioning device according to the X-Y correction amount so that the wafer moves in the horizontal plane of the rotating platform module of the wafer positioning device so that the center of the wafer is aligned with the specified position of the rotating platform module.

Description

Wafer positioning device and method

The present invention relates to a wafer positioning device and method, and in particular to a wafer positioning device and method that can detect non-transparent silicon wafers and semi-transparent wafers of special materials and can support the judgment of different positioning characteristics.

Before the wafer enters the semiconductor manufacturing equipment, it needs to be positioned first. Therefore, the outer edge of the wafer will be designed with positioning features, such as notch-type positioning features. The wafer positioning device for wafer positioning is also called a wafer edge finder, and the wafer positioning device is mainly used to find the position of the positioning features on the outer edge of the wafer (which is the angle of the positioning features) and perform eccentricity correction (including correction of the X-Y compensation amount (X-Y axis) and correction of the compensation angle (θ axis)). After the wafer is calibrated, its center will be aligned with the specified position of the rotating platform carrying the wafer, and the wafer will be rotated to a specified angle. Then the rotating platform carrying the wafer will send the wafer to the semiconductor manufacturing equipment for subsequent processes. The specified position usually refers to the home position of the rotating platform. The home position is an unchanging position, and when the wafer is scheduled to enter the next process, the positioning feature needs to be rotated to a specified angle.

The approved patent No. TW I735315 of the Republic of China provides a method and system for detecting the position of a wafer. The detection method is described as follows: first, a rotating platform rotates in one direction at a relatively fast speed to drive a wafer placed on the rotating platform and having a positioning feature on its outer edge to rotate, and at the same time, a detector detects the outer edge of the wafer to generate a detection result for a controller, and each detection result corresponds to a rotation angle of the rotating platform; When the positioning feature passes the detector, the rotating platform rotates in the opposite direction at a slower speed to drive the wafer to rotate in the opposite direction. At the same time, the detector detects the outer edge of the wafer rotating in the opposite direction to generate a detection result for the controller; and when the positioning feature of the wafer passes the detector again, the rotating platform stops rotating, and the controller estimates the eccentric position of the wafer and the position of the positioning feature based on the accumulated detection results and the corresponding rotation angle.

However, the detection method of the above-mentioned approved patent requires the rotating platform to rotate more than twice, and according to the detailed description of the above-mentioned approved patent, the wafer in the above-mentioned approved patent cannot be a wafer of a translucent material, and the positioning feature must be a notch-type positioning feature. Therefore, the industry still needs a wafer positioning device and method that can reduce the number of rotations of the rotating platform and support various types of wafers and various types of positioning features.

In order to solve the above technical problems, the present invention provides a wafer positioning device and method, which mainly calculates the first-order derivative and the second-order derivative of the image data of the wafer outer edge to find the approximate position of the positioning feature of the wafer outer edge, and then calculates the exact position (i.e., the exact angle) of the positioning feature through polynomial regression. After that, the positioning feature in the image data is excluded, and the positioning feature is calculated based on the image data without the positioning feature. The center offset of the wafer is used to calculate the correction angle based on the precise position of the positioning feature and the center offset, and the X-Y correction is calculated based on the correction angle and the center offset. Finally, the X-axis moving mechanism, Y-axis moving mechanism and θ-axis rotating mechanism of the rotating platform are controlled based on the calculated correction angle and the X-Y correction to align the center of the wafer with the specified position of the rotating platform and rotate the positioning feature of the wafer to the specified angle.

Based on at least one purpose of the present invention, the present invention provides a wafer positioning device, and the wafer positioning device includes a rotating platform module, a light source, an image capture device, a controller and a driving device. The rotating platform module is used to carry a wafer and rotate the wafer. The light source is arranged on the outer side of the rotating platform module and is used to emit light to illuminate the outer edge of the wafer. The image capture device is arranged on the outer side of the rotating platform module and faces the light source, and is used to obtain image data of the outer edge of the wafer. The controller is electrically connected to the light source and the image capture device, and is used to receive image data, and calculate the precise position of the positioning feature of the outer edge of the wafer through the first-order derivative and the second-order derivative of the image data in combination with a polynomial regression operation, and after excluding the positioning feature in the image data, the center offset of the wafer is calculated based on the image data excluding the positioning feature, and the correction angle is calculated based on the precise position of the positioning feature and the center offset, and the X-Y correction amount is calculated based on the correction angle and the center offset. The driving device is electrically connected to the controller and is also connected to the rotating platform module. The controller controls the driving device to drive the rotating platform module to rotate according to the correction angle so that the positioning feature rotates to a specified angle (when the wafer is scheduled to enter the next process, the positioning feature needs to rotate to a specified angle), and the controller controls the driving device to drive the rotating platform module according to the X-Y correction amount so that the wafer moves in the horizontal plane of the rotating platform module so that the center of the wafer is aligned with the specified position of the rotating platform module (the specified position refers to the home position of the rotating platform module).

Optionally, in the above-mentioned embodiment of the wafer positioning device, the controller calculates the approximate position of the positioning feature based on the first-order derivative and the second-order derivative of the image data, and then performs multiple iterative calculations using polynomial regression operations based on the approximate position to calculate the precise position of the positioning feature, wherein the precise position is the precise angle of the positioning feature.

Optionally, in the above-mentioned embodiment of the wafer positioning device, the controller excludes the positioning features of the precise position in the image data, and finds the corresponding circle equation based on the image data excluding the positioning features to obtain the center offset.

Optionally, in the above-mentioned embodiment of the wafer positioning device, the wafer (WF) is a non-transparent silicon wafer or a wafer made of a semi-transparent material.

Optionally, in the above-mentioned embodiment of the wafer positioning device, the positioning feature of the wafer (WF) is a notch type positioning feature, a double flat edge type positioning feature or a single flat edge type positioning feature.

Optionally, in the above-mentioned embodiment of the wafer positioning device, the controller controls the driving device to drive the rotating platform module to rotate at least 360 degrees, and the image data captured by the image capturing device is the image data of the outer edge of the wafer rotated at least 360 degrees.

Optionally, in the above-mentioned embodiment of the wafer positioning device, the controller sets the brightness of the light source and the sensitivity of the image capture device according to the instructions input by the operator, wherein the operator determines the input instructions according to the type of wafer.

Optionally, in the above-mentioned embodiment of the wafer positioning device, the rotating platform module includes a θ-axis rotating mechanism, a Y-axis moving mechanism and an X-axis moving mechanism, wherein the θ-axis rotating mechanism is used to be driven by a driving device to rotate the rotating platform module, and the Y-axis moving mechanism and the X-axis moving mechanism are used to be driven by the driving device to move the wafer in the horizontal plane of the rotating platform module.

Based on at least one purpose of the present invention, the present invention provides a wafer positioning method, which includes the following steps: starting a light source and an image capture module, wherein the light source and the image capture module are arranged opposite to each other and face the outer edge of a wafer carried by a rotating platform module, and are located on the outer side of the rotating platform module; using a controller to control a driving device to drive the rotating platform module to rotate at least 360 degrees, so as to drive the wafer carried by the rotating platform module to rotate at least 360 degrees; using an image capture device to obtain image data of the outer edge of the wafer; using a controller to calculate the approximate position of a positioning feature according to the first-order derivative and the second-order derivative of the image data, and then using a polynomial regression operation to perform multiple iterations of calculations according to the approximate position to calculate the precise position of the positioning feature. The invention relates to a method for determining a position of a wafer having a wafer center offset of the wafer and a precise position of the wafer. The method comprises: determining a position of the wafer having a precise position in the image data, wherein the precise position is the precise angle of the positioning feature; excluding the positioning feature at the precise position in the image data by using a controller, and finding a corresponding circle equation according to the image data excluding the positioning feature to obtain a center offset of the wafer; calculating a correction angle according to the precise position of the positioning feature and the center offset, and calculating an X-Y correction according to the center offset and the correction angle; controlling a driving device according to the controller to drive a rotating platform module to rotate according to the correction angle so that the positioning feature rotates to a specified angle, and controlling a driving device according to the controller to drive the rotating platform module to move the wafer in a horizontal plane of the rotating platform module so that the center of the wafer is aligned with the specified position of the rotating platform module.

Optionally, in the above-mentioned embodiment of the wafer positioning method, the wafer is a non-transparent silicon wafer or a wafer made of a translucent material, and the positioning feature of the wafer is a notch type positioning feature, a double flat edge type positioning feature or a single flat edge type positioning feature.

In summary, compared with the prior art, the wafer positioning device and method of the present invention can reduce the number of rotations of the rotating platform and can support various types of wafers and various types of positioning features.

In order to help the examiner understand the technical features, contents and advantages of the present invention and the effects that can be achieved, the present invention is described in detail as follows with the accompanying drawings and in the form of embodiments. The drawings used therein are only for illustration and auxiliary description, and may not be the true proportions and precise configurations after the implementation of the present invention. Therefore, it should not be interpreted based on the proportions and configurations of the attached drawings to limit the scope of rights of the present invention in actual implementation.

Please refer to FIG. 1 , which is a schematic diagram of a wafer positioning device of an embodiment of the present invention. The wafer positioning device 1 includes a rotating platform module 11, a light source 12, an image capture device 13, a controller 14, and a driving device 15. In addition to being a rotatable platform for carrying a wafer WF, the rotating platform module 11 further includes a θ-axis rotating mechanism 111, a Y-axis moving mechanism 112, and an X-axis moving mechanism 113. The controller 14 is electrically connected to the light source 12, the image capture device 13, and the driving device 15, and the θ-axis rotating mechanism 111, the Y-axis moving mechanism 112, and the X-axis moving mechanism 113 are connected to the driving device 15.

The light source 12 is disposed below the outer side of the rotating platform module 11, and the image capture device 13 is disposed above the outer side of the rotating platform module 11, and the light source 12 and the image capture device 13 are disposed corresponding to each other. When the wafer WF is placed on the rotating platform module 11, the light emitted by the light source 12 will be directed to the outer edge of the wafer WF, and the image capture device 13 will capture the image data of the outer edge of the wafer WF. The light source 12 can be a laser diode or other directional light source, for example, a directional light source formed by a light-emitting diode and a convex lens. The image capture device 13 can be a charge coupled device (CCD) imaging device or other types of imaging devices. In addition, the present invention does not limit the types of the light source 12 and the image capture device 13.

The controller 14 can rotate the θ-axis rotating mechanism 111 by controlling the driving device 15 (e.g., a driving motor or other types of actuators), thereby driving the platform of the rotating platform module 11 to rotate, so that the wafer WF carried by the rotating platform module 11 also rotates. In addition, the controller 14 can also control the driving device 15 to make the Y-axis moving mechanism 112 and the X-axis moving mechanism 113 move the wafer WF carried by the rotating platform module 11 on the horizontal plane (X-Y axis plane) of the platform. The Y-axis moving mechanism 112 and the X-axis moving mechanism 113 can, for example, enable the platform and the wafer WF to move in a horizontal plane (X-Y axis plane), and the θ-axis rotating mechanism 111 can be a central rotating shaft disposed under the platform and connected to the platform, but the present invention does not limit the implementation method of the θ-axis rotating mechanism 111, the Y-axis moving mechanism 112, and the X-axis moving mechanism 113.

Furthermore, the controller 14 can also be used to set the intensity of the light source 12 and the sensitivity of the image capture device 13. In this way, the wafer positioning device 1 of the present invention can have a more precise positioning accuracy for different types of wafers WF. Please note that since the wafer positioning device 1 of the present invention mainly calculates the precise position of the positioning feature of the wafer WF (i.e., the precise angle of the positioning feature) through the first-order derivative and the second-order derivative of the image data of the outer edge of the wafer in combination with a polynomial regression operation, the controller 14 is used to set the intensity of the light source 12 and the sensitivity of the image capture device 13 only to further improve the positioning accuracy, and this practice is not a necessary limitation of the present invention.

Please refer to Figures 1 to 3. Figure 2 is a schematic flow chart of the wafer positioning method of the embodiment of the present invention, and Figure 3 is a detailed flow chart of the steps of finding the wafer positioning feature and calculating the precise position and center offset of the wafer positioning feature of the wafer. The controller 14 is usually a microcontroller unit that can be written into a firmware program (but the present invention is not limited to this, and can also be implemented using a pure hardware circuit), and the wafer positioning method of the present invention is mainly executed by the controller 14.

In step S21, the light source 12 and the image capture device 13 are activated. The wafer positioning device 1 of the present invention can support different types of wafers WF. The wafer WF can be a non-transparent silicon wafer or a semi-transparent wafer made of a special material. In order to improve the accuracy of positioning, in step S21, the operator can also input instructions to the controller 14 according to the type of wafer WF to set the intensity of the light source 12 and the sensitivity of the image capture device 13. Next, in step S22, the fixture places the wafer WF on the platform of the rotating platform module 11. At this time, the center of the wafer WF may deviate from the specified position of the rotating platform module 11 (usually referred to as the home position), and the positioning feature has not turned to the specified angle when entering the next process. Therefore, the positioning device 4 is required to detect the wafer WF to position the wafer WF.

In step S23, the controller 14 controls the driving device 15 to drive the θ-axis rotating mechanism 111 to rotate the platform of the rotating platform module 11 by 360 degrees to 720 degrees, so that the image capturing device 13 can obtain the image data of the outer edge of the wafer WF in step S24. Next, in step S25, the controller 14 searches for the approximate position of the positioning feature of the wafer WF based on the image data of the outer edge of the wafer WF obtained, wherein the method of searching for the approximate position of the positioning feature of the wafer WF is to first calculate the first-order derivative and the second-order derivative of the image data of the outer edge of the wafer WF to eliminate the center offset (i.e., X-Y offset), and find the approximate position of the positioning feature of the outer edge of the wafer WF through the rate of change of the first-order derivative and the second-order derivative, and then, and then, according to the approximate position, use polynomial regression operation to perform multiple iterations to calculate the precise position of the positioning feature, wherein the precise position of the positioning feature is the angle of the positioning feature, wherein the positioning feature is not limited to a notch-type positioning feature, and can also be a single flat edge, double flat edges or other types of positioning features. In step S25, the controller 14 excludes the positioning features of the precise position in the image data, and finds the center offset based on the image data without the positioning features.

Then, in step S26, the controller 14 calculates the compensation angle of the wafer WF according to the precise position of the positioning feature and the center offset, and calculates the X-Y compensation amount according to the compensation angle and the center offset. Finally, in step S27, the controller 14 compensates for the offset of the wafer via the X-axis moving mechanism 113, the Y-axis moving mechanism 112 and the θ-axis rotating mechanism 111. Specifically, the controller 14 controls the drive device 15 to drive the θ-axis rotation mechanism 111 to rotate the platform according to the calculated correction angle of the wafer WF, so that the positioning feature of the wafer WF rotates to the specified angle, and the controller 14 controls the drive device 15 to drive the Y-axis movement mechanism 112 and the X-axis movement mechanism 113 to move the wafer WF in the horizontal plane according to the calculated X-Y correction amount, so that the center of the wafer WF is aligned with the specified position of the platform.

In step S24, the controller 14 will also check whether the index of the image data is continuous and check the angle difference between the wafer WF before and after rotation. If the index of the image data is not continuous (because if the rotation speed is too fast, the image data may be missing, so it is necessary to check) or the angle difference between the wafer WF before and after rotation is less than 360 degrees (because there may be an operational error or other factors that cause the platform of the rotating platform module 11 to not rotate more than 360 degrees), it is necessary to perform steps S23 and S24 again to re-acquire valid image data of the outer edge of the wafer WF.

Furthermore, as shown in FIG3 , step S25 includes steps S251 to S256. In step S251, the controller 14 performs a moving average process on the image data to filter out most of the noise in the image data. Please note that step S251 is not a necessary step, but in most cases, in order to increase the positioning accuracy, step S251 will inevitably be executed. Then, in step S252, the controller 14 calculates the first-order derivative and the second-order derivative of the image data. The first-order derivative of the image data is the slope function of the image data. Where the slope function is 0, it may be where the extreme value occurs, which is the possible position of the positioning feature. The second-order derivative of the image data can be used to determine where the slope changes the most. Usually, the location of the positioning feature is where the slope changes the most. In addition, before performing step S252, the controller 14 can first check whether the brightness setting of the light source 12, the sensitivity setting of the image capture device 13, and the angle difference before and after the platform rotates are correct to avoid unnecessary calculations.

In step S253, the controller 14 finds the maximum and minimum values of the first-order derivative of the image data. In step S253, the controller 14 also determines whether the rotation angles corresponding to the maximum and minimum values of the first-order derivative are close, that is, whether the difference between the two occurrence positions of the maximum and minimum values of the first-order derivative is less than a specific threshold value. If the rotation angles corresponding to the maximum and minimum values of the first-order derivative are close, the subsequent calculations will be further performed. In step S253, the controller 14 also checks whether the maximum and minimum values of the image data are out of range. If they are out of range, the subsequent calculations will not be performed.

Then, in step S254, the controller 14 uses the second-order derivative and the first-order derivative of the image data to find the approximate position of the positioning feature. Furthermore, the maximum and minimum values of the first-order derivative previously found may be the positions of the maximum change of the image data, so the positions of the maximum and minimum values of the first-order derivative can be used to narrow the range of finding the positioning feature. In short, the controller 14 uses the first-order derivative of the image data to narrow the range of finding the positioning feature, and then uses the second-order derivative of the image data to find the approximate position of the positioning feature in the above-mentioned narrowed range.

Next, in step S255, the controller 14 uses polynomial regression operations to perform multiple iterations of calculations based on the approximate position of the positioning feature to calculate the precise position of the positioning feature (including the angle of the positioning feature). Then in step S256, the controller 14 excludes the portion of the positioning feature at the precise position in the image data, and finds the corresponding circle equation based on the image data excluding the positioning feature to obtain the center offset of the wafer WF.

The polynomial regression operation in step S255 is explained as follows. The approximate position θ _coarse of the positioning feature can be obtained by calculating the first-order derivative and the second-order derivative of the image data, and the difference Diff between the maximum value and the minimum value near the approximate position in the image data can also be calculated. Furthermore, when the positioning feature falls on the approximate position θ _coarse , the approximate center offset D _coarse between the center point of the wafer WF and the specified position (original position) is known, the image value ccd of the approximate position θ _coarse of the positioning feature is also known, and the radius R of the wafer WF is also known, so the following operation formula is used: ccd=Diff+D _coarse *cos(θ _O )-[R ² -D _coarse ² *sin ² (θ _O )] ^1/2 , and the precise position θ _O of the positioning feature is obtained. In the present invention, the number of iterations is 1000, but the present invention is not limited thereto. Then, after calculating the precise position θ _O of the positioning feature, the controller 14 can exclude the positioning feature of the precise position in the image data, and find the corresponding circle equation based on the image data excluding the positioning feature, and obtain the center offset D.

After calculating the precise position θ _O and the center offset D of the positioning feature, the correction angle θ and the XY correction values D _x and D _y are calculated in step S26 as follows. To be added, D _x is the X-axis correction component of the correction value D, and D _y is the Y-axis correction component of the correction value D. Please refer to Figures 4 and 5. The radius R of the wafer WF, the center offset D, the precise position θ _O (precise angle) of the positioning feature, the target angle θ _t of the positioning feature relative to the horizontal axis of the wafer WF center point, and the direction angle θ _n of the positioning feature are known. Therefore, θ _a =θ _O -θ _n , d = D*sin(θ _a ) and θ _e =θ _b = sin ^-1 (d/R) can be calculated. Without considering the error caused by the notch type positioning feature, the correction angle θ = θ _t -θ _n +θ _e can be calculated. Then, please refer to Figure 6. Then, according to the correction angle θ and the center offset, the XY correction amount D _x = D*cos(θ+θ _O ) and D _y = D*sin(θ+θ _O ) can be calculated. The calculations in Figures 4 to 6 are for notch-type positioning features, but the present invention is not limited to the type of positioning features. Please refer to Figure 7, the calculation method of the correction angle θ and the XY correction amount D _x , D _y of the single flat edge type positioning feature is the same as the calculation method of the correction angle θ and the XY correction amount D _x , D _y of the notch type positioning feature, but θ _e will be equal to 0, so the correction angle θ=θ _t -θ _n .

In summary, since the wafer positioning device and method provided by the present invention mainly finds the positioning features through the first-order derivative and the second-order derivative of the image data of the wafer periphery in combination with a polynomial regression operation, it is not necessary to rotate the rotating platform more than twice, and the type of wafer and the type of positioning features are not limited. In other words, compared with the prior art, the wafer positioning device and method of the present invention can make the rotating platform rotate less times and can support various types of wafers and various types of positioning features.

The embodiments described above are only for illustrating the technical ideas and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly. They cannot be used to limit the patent scope of the present invention. In other words, all equivalent changes or modifications made according to the spirit disclosed by the present invention should still be included in the patent scope of the present invention.

1: Wafer positioning device 11: Rotating platform module 111: θ axis rotation mechanism 112: Y axis movement mechanism 113: X axis movement mechanism 12: Light source 13: Image capture device 14: Controller 15: Driving device S21~S27, S251~S256: Step θ: Correction angle _θa , _θe , _θb : Angle d: Triangle height D: Center offset R: Radius _θO : Accurate position _θt : Target angle _θn : Direction angle WF: Wafer

The accompanying drawings are provided to enable a person with ordinary knowledge in the art to which the present invention belongs to further understand the present invention, and are incorporated into and constitute a part of the specification of the present invention. The accompanying drawings show exemplary embodiments of the present invention, and are used together with the specification of the present invention to explain the principles of the present invention.

FIG. 1 is a schematic diagram of a wafer positioning device according to an embodiment of the present invention.

FIG. 2 is a schematic flow chart of a wafer positioning method according to an embodiment of the present invention.

FIG. 3 is a detailed flow chart of the steps of finding wafer positioning features and calculating the precise position and center offset of the wafer in the wafer positioning method according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of the correction angle of the wafer in the wafer positioning method according to an embodiment of the present invention.

FIG. 5 is another schematic diagram of the correction angle of the wafer in the wafer positioning method according to the embodiment of the present invention.

FIG6 is a schematic diagram of the X-Y correction amount of the wafer in the wafer positioning method according to an embodiment of the present invention.

FIG. 7 is a schematic diagram of the X-Y correction amount of another wafer in the wafer positioning method of the embodiment of the present invention.

1: Wafer positioning device

11: Rotating platform module

111: θ-axis rotation mechanism

112: Y-axis moving mechanism

113: X-axis moving mechanism

12: Light source

13: Image capture device

14: Controller

15: Drive device

WF: Wafer

Claims (10)

A wafer positioning device comprises: A rotating platform module (11) for carrying a wafer (WF) and for rotating the wafer (WF); A light source (12) disposed on an outer side of the rotating platform module (11) and for emitting a light to illuminate an outer edge of the wafer (WF); An image capture device (13) disposed on the outer side of the rotating platform module (11) and facing the light source (12) for acquiring image data of the outer edge of the wafer (WF); A controller (14) is electrically connected to the light source (12) and the image capture device (13), and is used to receive the image data, and calculate the precise position of a positioning feature of the outer edge of the wafer (WF) through a first-order derivative and a second-order derivative of the image data in conjunction with a polynomial regression operation, and after excluding the positioning feature from the image data, calculate a center offset of the wafer (WF) based on the image data excluding the positioning feature, and calculate a correction angle based on the precise position of the positioning feature and the center offset, and calculate an X-Y correction based on the center offset and the correction angle; and A driving device (15) is electrically connected to the controller (14) and the rotating platform module (11), wherein the controller (14) controls the driving device (15) to drive the rotating platform module (11) to rotate according to the correction angle so that the positioning feature rotates to a specified angle, and the controller (14) controls the driving device (15) to drive the rotating platform module (11) according to the X-Y correction amount so that the wafer (WF) moves in a horizontal plane of the rotating platform module (11) so that a center of the wafer (WF) is aligned with a specified position of the rotating platform module (11). A wafer positioning device as described in claim 1, wherein the controller (14) calculates an approximate position of the positioning feature based on the first-order derivative and the second-order derivative of the image data, and then performs multiple iterative calculations using the polynomial regression operation based on the approximate position to calculate an exact position of the positioning feature, wherein the exact position is an exact angle of the positioning feature. A wafer positioning device as described in claim 2, wherein the controller (14) excludes the positioning feature of the precise angle in the image data, and finds a corresponding circle equation based on the image data excluding the positioning feature to thereby determine the center offset. The wafer positioning device as described in claim 1, wherein the wafer (WF) is a non-transparent silicon wafer or a wafer of a translucent material. A wafer positioning device as described in claim 1, wherein the positioning feature of the wafer (WF) is a notch type positioning feature, a double flat edge type positioning feature or a single flat edge type positioning feature. A wafer positioning device as described in claim 1, wherein the controller (14) controls the driving device (15) to drive the rotating platform module (11) to rotate at least 360 degrees, and the image data captured by the image capture device (13) is image data of the outer edge of the wafer (WF) rotated at least 360 degrees. A wafer positioning device as described in claim 1, wherein the controller (14) sets a brightness of the light source (12) and a sensitivity of the image capture device (13) according to an instruction input by an operator, wherein the operator determines the input instruction according to a type of the wafer (WF). As described in claim 1, the rotating platform module (11) includes a θ-axis rotating mechanism (111), a Y-axis moving mechanism (112) and an X-axis moving mechanism (113), wherein the θ-axis rotating mechanism (111) is used to be driven by the driving device (15) to rotate the rotating platform module (11), and the Y-axis moving mechanism (112) and the X-axis moving mechanism (113) are used to be driven by the driving device (15) to move the wafer (WF) in the horizontal plane of the rotating platform module (11). A wafer positioning method comprises: Activating a light source (12) and an image capture module (13), wherein the light source (12) and the image capture module (13) are arranged opposite to each other and face an outer edge of a wafer (WF) carried by a rotating platform module (11), and are located on an outer side of a rotating platform module (11); Using a controller (14) to control a driving device (15) to drive the rotating platform module (11) to rotate at least 360 degrees, so as to drive the wafer (WF) carried by the rotating platform module (11) to rotate at least 360 degrees; Using the image capture device (13) to obtain image data of the outer edge of the wafer (WF); Using the controller (14) to calculate an approximate position of a positioning feature based on a first-order derivative and a second-order derivative of the image data, and then using a polynomial regression operation to perform multiple iterations based on the approximate position to calculate an exact position of the positioning feature, wherein the exact position is an exact angle of the positioning feature; Using the controller (14) to exclude the positioning feature of the exact angle in the image data, and find a corresponding circle equation based on the image data excluding the positioning feature to obtain a center offset of the wafer (WF); Using the controller (14) to calculate a correction angle based on the exact position of the positioning feature and the center offset, and calculate an X-Y correction based on the correction angle and the center offset; and The controller (14) controls the driving device (15) to drive the rotating platform module (11) to rotate according to the correction angle so that the positioning feature rotates to a specified angle, and the controller (14) controls the driving device (15) to drive the rotating platform module (11) according to the X-Y correction amount so that the wafer (WF) moves in a horizontal plane of the rotating platform module (11) so that a center of the wafer (WF) is aligned with a specified position of the rotating platform module (11). A wafer positioning method as described in claim 9, wherein the wafer (WF) is a non-transparent silicon wafer or a wafer of a translucent material, and the positioning feature of the wafer (WF) is a notch type positioning feature, a double flat edge type positioning feature or a single flat edge type positioning feature.