Wafer one-dimensional warpage measuring device, method and wafer measuring system

Abstract

The application discloses a wafer one-dimensional warping degree measuring device, a wafer one-dimensional warping degree measuring method and a wafer measuring system. The wafer one-dimensional warping degree measuring device comprises a first motion platform, an image acquisition device, a distance measuring module and a controller. The controller controls the first motion platform to move according to a to-be-measured point positioned by the image acquisition device until the to-be-measured point coincides with a midpoint of a line connecting two measuring points of the distance measuring module on the wafer surface, then reads distance data of the two measuring points uploaded by the distance measuring module, and calculates a one-dimensional inclination angle of the to-be-measured point along a direction of a line connecting two projection points of the two measuring points on a vertical plane according to the distance data. The application can realize accurate positioning of a to-be-measured point on a wafer and accurate measurement of a one-dimensional warping degree of the to-be-measured point.

Description

Technical Field

[0001] This application relates to the field of wafer warpage detection technology, and in particular to a wafer one-dimensional warpage measurement device, method and wafer measurement system. Background Technology

[0002] The immense computing power demands brought about by AI necessitate higher unit computing density and lower power consumption, thus spurring the rapid development of NAND and DRAM. As NAND and DRAM evolve towards 3D process structures, the linewidth of etched structures in semiconductor devices is becoming increasingly smaller, while the etch depth is increasing, resulting in unique high aspect ratio (HAR) structures. Etching of HAR structures is a critical and challenging process step in semiconductor device manufacturing, significantly impacting device performance and yield. For example... Figure 1 As shown, with the advancement of semiconductor memory chip manufacturing technology and the gradual increase in aspect ratio, wafers experience greater bending and warping, resulting in a non-zero one-dimensional tilt angle of the wafer on the measurement stage relative to the reference plane. CD-SAXS (Critical Dimension Small Angle X-ray Scattering) measurement technology relies on iterative model fitting to solve the scattering signals from different incident angles of the wafer.

[0003] Since CD-SAXS is used for the metrology of patterned NAND wafers, to achieve accurate measurement of deep-hole structural units within a specific grain area on the wafer, it is first necessary to accurately measure the tilt angle caused by wafer warping, and then perform tilt angle compensation correction during the CD-SAXS measurement process. However, existing CD-SAXS measurement technology cannot accurately locate the measurement point or perform high-precision tilt angle compensation, resulting in inaccurate final measurement results. Summary of the Invention

[0004] In view of this, this application provides a wafer one-dimensional warp measurement device, method and wafer measurement system to solve the problem that the existing CD-SAXS measurement technology fails to accurately locate the test point before performing tilt measurement and compensation.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide a one-dimensional wafer warpage measurement device, which includes: a first motion platform for carrying the wafer to be measured; an image acquisition device for capturing images of the wafer surface and locating the test point on the wafer based on the images; a ranging module for forming two measurement points on the wafer surface and acquiring distance data between the ranging module and the two measurement points; and a controller electrically connected to the first motion platform, the image acquisition device, and the ranging module, for controlling the movement of the first motion platform according to the test point located by the image acquisition device, so that the test point coincides with the midpoint of the line connecting the two measurement points, then reading the distance data uploaded by the ranging module, and calculating the one-dimensional tilt angle of the test point along the line connecting the projection points of the two measurement points on the vertical plane based on the distance data.

[0006] As a further improvement to this application, the ranging module includes two spectral confocal rangefinders or two laser interferometric rangefinders.

[0007] As a further improvement of this application, a visual standard sample is also provided on the first motion platform to calibrate the relative spatial position of the image acquisition device and the ranging module, so as to determine the relative positional relationship between the field of view center of the image acquisition device and the midpoint of the line connecting the two measurement points; the controller is also used to control the movement of the first motion platform so that the point to be measured coincides with the field of view center, and then drive the first motion platform to move according to the relative positional relationship so that the point to be measured coincides with the midpoint of the line connecting the two measurement points.

[0008] As a further improvement to this application, the distance data between the ranging module and the two measuring points is represented as H. i (Z1, Z2), where Z1 represents the distance data of the first measurement point from the ranging module, Z2 represents the distance data of the second measurement point from the ranging module, and i represents the i-th measurement point;

[0009] The calculation process for a one-dimensional tilt angle is expressed as follows:

[0010]

[0011] Where θ represents a one-dimensional tilt angle, X1 represents the x-coordinate of the first measurement point, and X2 represents the x-coordinate of the second measurement point.

[0012] As a further improvement of this application, it also includes a second motion platform, on which the image acquisition device and the ranging module are disposed. The second motion platform is used to move the image acquisition device and the ranging module between a preset standby position and a preset measurement position.

[0013] To solve the above-mentioned technical problems, another technical solution adopted in this application is: providing a method for measuring the one-dimensional warpage of a wafer, which is applied to one of the wafer one-dimensional warpage measuring devices mentioned above. The wafer one-dimensional warpage measuring device includes a first motion platform, an image acquisition device, a ranging module, and a controller. The method includes: the image acquisition device capturing a surface image of the wafer on the first motion platform and sending it to the controller; the controller identifying the point to be measured based on a visual algorithm and determining the coordinate position of the point to be measured; the controller driving the first motion platform until the point to be measured coincides with the midpoint of the line connecting two measuring points on the wafer surface of the ranging module; the ranging module reading the distance data between the ranging module and the two measuring points and uploading the distance data to the controller; and the controller calculating the one-dimensional tilt angle of the point to be measured along the line connecting the projection points of the two measuring points on the vertical plane based on the distance data.

[0014] As a further improvement of this application, after the controller calculates the one-dimensional tilt angle of the test point along the line connecting the projection points of the two measurement points on the vertical plane based on the distance data, it further includes: the controller periodically drives the first motion platform to move according to a preset step size, so that the midpoint of the line connecting the two measurement points moves to the new test point, and each time it moves to the new test point, it acquires the distance data corresponding to the new test point collected by the distance measuring module, and calculates the one-dimensional tilt angle of the new test point along the line connecting the projection points of the two measurement points on the vertical plane based on the corresponding distance data of the new test point.

[0015] As a further improvement to this application, the calculation process for the one-dimensional tilt angle is expressed as follows:

[0016]

[0017] Where θ represents a one-dimensional tilt angle, Z1 represents the distance data of the first measurement point from the ranging module, Z2 represents the distance data of the second measurement point from the ranging module, i represents the i-th measurement point, X1 represents the x-coordinate value of the first measurement point, and X2 represents the x-coordinate value of the second measurement point.

[0018] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide a wafer measurement system, which includes a light source module, a vacuum scattering tube, a detection module, and one of the above-mentioned wafer one-dimensional warp degree measurement devices. The wafer one-dimensional warp degree measurement device includes a first motion platform, an image acquisition device, a ranging module, and a controller. X-rays emitted by the light source module pass through the vacuum scattering tube and irradiate the test point of the wafer on the first motion platform. The controller calculates the one-dimensional tilt angle of the test point along the line connecting the projection points of the two measurement points on the vertical plane based on the distance data corresponding to the two measurement points uploaded by the ranging module. The controller controls the rotation of the first motion platform according to the one-dimensional tilt angle to perform surface tilt angle compensation. The detection module is used to acquire the scattering image formed by X-rays irradiating the test point of the wafer after tilt angle compensation.

[0019] As a further improvement of this application, the wafer one-dimensional warp measurement device also includes a second motion platform, on which the image acquisition device and the ranging module are mounted; the controller is also used to control the second motion platform to move the image acquisition device and the ranging module from a preset standby position to a preset measurement position before measuring the wafer to measure the one-dimensional tilt angle of the point to be measured and to compensate for the tilt angle, and then move the image acquisition device and the ranging module from the preset measurement position back to the preset standby position.

[0020] The beneficial effects of this application are:

[0021] The wafer one-dimensional warpage measurement device of this application locates the test point on the wafer using an image acquisition device, and then moves the wafer by moving the first motion platform so that the test point on the wafer coincides with the midpoint of the line connecting the two measurement points on the wafer surface of the ranging module. The ranging module then measures the distance between the two measurement points and the ranging module, and uses the distance data to calculate the one-dimensional tilt angle of the test point along the line connecting the projection points of the two measurement points on the vertical plane. This achieves precise positioning of the test point and accurate measurement of the one-dimensional warpage of the test point. Moreover, the one-dimensional warpage of the test point can be calculated by simultaneously measuring the distance between the two test points, resulting in faster measurement speed and ensuring accurate wafer measurement in CD-SAXS measurement technology. Attached Figure Description

[0022] Figure 1 A schematic diagram illustrating wafer bending and warping.

[0023] Figure 2 This is a schematic diagram of the structure of the wafer one-dimensional warp measurement device according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the electrical connections of the wafer one-dimensional warp measurement device according to an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the measurement points of the wafer one-dimensional warp measurement device and the field of view of the image acquisition device according to an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the distance measuring instrument measuring data of the wafer one-dimensional warp degree measuring device according to an embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of the image acquisition device and the ranging module of the wafer one-dimensional warp measurement device according to an embodiment of the present invention during movement;

[0028] Figure 7This is a flowchart illustrating the method for measuring the one-dimensional warpage of a wafer according to an embodiment of the present invention.

[0029] Figure 8 This is a schematic diagram of the wafer one-dimensional warp measurement method according to a preset step size when measuring the one-dimensional tilt angle.

[0030] Figure 9 This is a schematic diagram of the structure of the wafer measurement system according to an embodiment of the present invention;

[0031] Figure 10 This is a schematic diagram of the image acquisition device and ranging module of the wafer measurement system according to an embodiment of the present invention during movement. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0033] The terms "first," "second," and "third" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative spatial positions and movements of components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0034] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0035] Figure 2 This is a schematic diagram of the structure of a wafer one-dimensional warp measurement device according to an embodiment of the present invention. Figure 2 As shown, the wafer one-dimensional warp measurement device includes: a first motion platform 1, an image acquisition device 2, a ranging module 3, and a controller 4 (see [reference]). Figure 3 (As shown).

[0036] The first motion platform 1 is a six-axis motion platform with six degrees of freedom, including three translational motion axes and three rotational degrees of freedom, so that the first motion platform 1 can drive the wafer 7 to translate or rotate.

[0037] Image acquisition device 2 is an optical microscope camera used to capture images of wafer 7 on the first motion platform 1 and locate the test point on the surface of wafer 7 from the images. The test point is a mark pre-marked on wafer 7 with a special pattern. During the location of the test point, image acquisition device 2 scans the surface of wafer 7 until the test point is found.

[0038] The ranging module 3 is used to form two measurement points on the surface of wafer 7, and a line segment can be constructed on the surface of wafer 7 using these two measurement points as vertices. The ranging module 3 measures the two measurement points respectively to obtain two distance data between the ranging module and the two measurement points.

[0039] The controller 4 is electrically connected to the first motion platform 1, the image acquisition device 2, and the ranging module 3, respectively, and is used to control the operation of the first motion platform 1, the image acquisition device 2, and the ranging module 3.

[0040] Specifically, when measuring the one-dimensional warpage of wafer 7, controller 4 first acquires the positioning coordinates of the point to be measured from image acquisition device 2, and then controls the first motion platform 1 to move according to these positioning coordinates, so that the point to be measured on wafer 7 coincides with the midpoint of the line connecting the two measurement points; then, controller 4 acquires the distance data uploaded by distance measurement module 3, and uses the distance data to calculate the one-dimensional tilt angle of the point to be measured along the line connecting the projection points of the two measurement points on the vertical plane. This one-dimensional tilt angle uses the vertical plane as a reference plane, and the direction of the straight line formed by the projection points of the two measurement points on the reference plane is the reference direction. The tilt angle formed by the point to be measured along the reference direction is the tilt angle formed by the point to be measured along the reference direction.

[0041] It should be noted that in this embodiment, the midpoint O2 of the line segment formed by the two measurement points is used as the target point, which can take into account both measurement points at both ends. By moving the point to be measured to the midpoint O2, the final measurement result can be more accurate.

[0042] The wafer one-dimensional warp measurement device in this embodiment locates the test point on the wafer 7 using the image acquisition device 2, and then moves the wafer 7 by moving the first motion platform 1 so that the test point on the wafer 7 coincides with the midpoint O2 of the line connecting the two measurement points on the surface of the wafer 7 by the ranging module 3. The ranging module 3 then measures the distance data between the two measurement points, and uses the distance data to calculate the one-dimensional tilt angle of the test point. This achieves accurate positioning of the test point and accurate measurement of the one-dimensional warp degree of the test point, providing a guarantee for accurate measurement of the wafer 7 in CD-SAXS measurement technology.

[0043] Furthermore, in some embodiments, the ranging module 3 includes two spectral confocal rangefinders or two laser interferometric rangefinders. Both spectral confocal rangefinders and laser interferometric rangefinders can be used for ranging in this embodiment, and this embodiment is not limited thereto.

[0044] Furthermore, based on the above implementation, in other embodiments, such as Figure 1 and Figure 4 As shown, a visual standard sample 5 is also provided on the first motion platform 1 to calibrate the relative spatial position of the image acquisition device 2 and the ranging module 3, so as to determine the relative positional relationship between the field of view center O1 of the image acquisition device 2 and the midpoint O2 of the line connecting the two measurement points. The controller 4 is also used to control the movement of the first motion platform 1 so that the point to be measured coincides with the field of view center O1, and then drive the first motion platform 1 to move according to the relative positional relationship so that the point to be measured coincides with the midpoint O2.

[0045] It should be noted that the image acquisition device 2 is preferably an optical microscope camera. For example... Figure 4 As shown, P1 and P2 are two measurement points. The field of view formed by the optical microscope on the surface of wafer 7 is a rectangular field of view. The optical microscope and the ranging module 3 are calibrated by using the visual standard sample 5, so as to obtain the relative positional relationship between the center O1 and the midpoint O2 of the rectangular field of view.

[0046] Specifically, during the scanning of the wafer 7 surface by the optical microscope camera, when the optical microscope camera identifies the point to be measured (such as...) Figure 4 After the Mark point is reached, the first motion platform 1 is controlled to move so that the point to be measured coincides with the center of the field of view O1 of the rectangular field of view. Then, the first motion platform 1 is driven to move again according to the relative positional relationship between the center of the field of view O1 and the midpoint O2 of the polygon so that the point to be measured coincides with the midpoint O2, thereby completing the positioning of the point to be measured.

[0047] In this embodiment, the field of view center O1 and midpoint O2 of the image acquisition device 2 are pre-calibrated using the visual standard sample 5. After obtaining the coordinate information of the point to be measured, the field of view center O1 of the image acquisition device 2 is used as a jump to achieve rapid overlap between the point to be measured and the midpoint O2. This eliminates the need to construct a coordinate system with the point to be measured and the midpoint O2, perform coordinate transformation calculations, and then achieve overlap between the point to be measured and the midpoint O2, thereby reducing the amount of computation and improving the measurement speed of the entire measurement process of the one-dimensional warp degree of the wafer 7.

[0048] Furthermore, in this embodiment, as Figure 5 As shown, P1 and P2 are two measurement points, and the distance between the ranging module and the two measurement points is represented as H. i (Z1, Z2), where Z1 represents the distance data of the first measurement point from the ranging module, Z2 represents the distance data of the second measurement point from the ranging module, and i represents the i-th measurement point;

[0049] The calculation process for a one-dimensional tilt angle is expressed as follows:

[0050]

[0051] Where θ represents a one-dimensional tilt angle, X1 represents the x-coordinate of the first measurement point, and X2 represents the x-coordinate of the second measurement point.

[0052] Furthermore, based on the above embodiments, in other embodiments, such as Figure 2 and Figure 6 As shown, the wafer one-dimensional warp measurement device also includes a second motion platform 6 electrically connected to the controller 4. The image acquisition device 2 and the ranging module 3 are mounted on the second motion platform 6. The second motion platform 6 is used to move the image acquisition device 2 and the ranging module 3 between a preset standby position and a preset measurement position.

[0053] It should be noted that in the CD-SAXS measurement technology, the wafer 7 on the first motion platform 1 needs to be perpendicularly irradiated by the X-rays emitted by the light source. However, when the image acquisition device 2 and the ranging module 3 are measuring the one-dimensional tilt angle of the point to be measured, they may pass through the X-ray optical path, causing X-ray obstruction. Therefore, in order to avoid interference between the image acquisition device 2 and the ranging module 3 and the X-ray optical path, in this embodiment, the image acquisition device 2 and the ranging module 3 are set on the second motion platform 6, and the image acquisition device 2 and the ranging module 3 are moved by the second motion platform 6. When a one-dimensional tilt angle measurement is required, the controller 4 controls the movement of the second motion platform 6, so that the image acquisition device 2 and the ranging module 3 move from the preset standby position to the preset measurement position. Then, the image acquisition device 2 and the ranging module 3 start working and measure the one-dimensional tilt angle of the point to be measured. After the measurement is completed, the controller 4 controls the movement of the second motion platform 6 again, so that the image acquisition device 2 and the ranging module 3 move from the preset measurement position to the preset standby position, thus avoiding X-ray obstruction.

[0054] Furthermore, after the second motion platform 6 moves the image acquisition device 2 and the ranging module 3 to the preset working position, it is also used to adjust the distance between the image acquisition device 2 and the ranging module 3 and the wafer 7, so that the image acquisition device 2 and the ranging module 3 can perform the positioning and ranging of the point to be measured at the same working distance.

[0055] Figure 7 This is a flowchart of a method for measuring one-dimensional wafer warpage according to an embodiment of the present invention. This method is applied to a one-dimensional wafer warpage measuring device described in one of the above embodiments. The device includes a first motion platform, an image acquisition device, a ranging module, and a controller. Figure 7 As shown, the method for measuring the one-dimensional warpage of a wafer includes:

[0056] Step S1: The image acquisition device captures a surface image of the wafer on the first motion platform and sends it to the controller.

[0057] Specifically, the image acquisition device selects a rectangular field of view of 1 to 10 mm according to different magnifications. When acquiring surface images of the wafer, the second stage 6 is first moved so that the center of the microscope's field of view coincides with the center of the wafer. Based on the 300 mm diameter circular surface of the 12-inch wafer, the approximate distance between the point to be measured and the center of the wafer is taken as 40 × 40 mm. The first stage is moved to scan until the point to be measured is scanned.

[0058] Step S2: The controller identifies the point to be measured based on a visual algorithm and determines the coordinate position of the point to be measured.

[0059] It should be noted that this visual algorithm can be implemented using machine learning algorithms.

[0060] Step S3: The controller drives the first motion platform until the point to be measured coincides with the midpoint of the line connecting the two measurement points on the wafer surface of the ranging module.

[0061] Step S4: The ranging module reads the distance data between the ranging module and the two measuring points, and uploads the distance data to the controller.

[0062] Step S5: The controller calculates the one-dimensional tilt angle of the point to be measured along the line connecting the projection points of the two measurement points on the vertical plane based on the distance data.

[0063] Specifically, for details of steps S1 to S5 in this embodiment, please refer to the above embodiment of the wafer one-dimensional warp measurement device, which will not be repeated here.

[0064] It should be noted that, in some embodiments, the wafer one-dimensional warpage measurement device further includes a second motion platform, on which the image acquisition device and the ranging module are mounted. The second motion platform is used to move the image acquisition device and the ranging module between a preset standby position and a preset measurement position. Therefore, before step S1, the following is also included:

[0065] The controller controls the movement of the second motion platform to move the image acquisition device and the ranging module from the preset standby position to the preset measurement position.

[0066] Following step S5, the following is also included:

[0067] The controller controls the movement of the second motion platform to move the image acquisition device and the ranging module from the preset measurement position to the preset standby position.

[0068] Specifically, to prevent the image acquisition device and ranging module from blocking the X-ray optical path when the one-dimensional wafer warpage measurement device is applied to the CD-SAXS measurement technology, this embodiment sets the image acquisition device and ranging module on the second motion platform. Before performing CD-SAXS measurement, the image acquisition device and ranging module are moved to a preset measurement position to achieve one-dimensional tilt angle measurement of the point to be measured. After the one-dimensional tilt angle measurement is completed, the image acquisition device and ranging module are moved to a preset standby position to avoid blocking the X-ray optical path during the CD-SAXS measurement process.

[0069] It should be noted that after the second motion platform moves to the preset measurement position, it is also used to fine-tune the distance between the image acquisition device and the ranging module and the wafer.

[0070] The wafer one-dimensional warpage measurement method of this embodiment locates the test point on the wafer using an image acquisition device, and then moves the wafer by moving the first motion platform so that the test point on the wafer coincides with the midpoint of the line connecting the two measurement points on the wafer surface of the ranging module. The ranging module is then used to measure the distance between the two measurement points and the ranging module. The one-dimensional tilt angle of the test point along the line connecting the projection points of the two measurement points on the vertical plane is then calculated using the distance data. This method achieves accurate positioning of the test point and accurate measurement of the one-dimensional warpage of the test point, providing a guarantee for accurate wafer measurement in CD-SAXS measurement technology.

[0071] Furthermore, in some embodiments, after step S5, the method further includes:

[0072] The controller periodically drives the first motion platform to move in a preset step size, so that the midpoint of the line connecting the two measurement points moves to a new measurement point. Each time it moves to a new measurement point, it acquires the distance data corresponding to the new measurement point collected by the distance measuring module, and calculates the one-dimensional tilt angle of the new measurement point along the line connecting the projection points of the two measurement points on the vertical plane based on the corresponding distance data of the new measurement point.

[0073] Specifically, in order to achieve gridded point-by-point scanning measurements of the wafer surface along the X and Y axes, thereby constructing a one-dimensional tilt angle measurement result for warped and bent wafers, in this embodiment, as follows... Figure 8 As shown, a two-dimensional coordinate system is constructed with the vertical plane as the reference plane. After the one-dimensional tilt angle measurement of the test point is completed, the controller controls the first motion platform to move a preset step distance along the X-axis or Y-axis, so that the midpoint of the line connecting the two measurement points moves to a new test point. Then, the one-dimensional tilt angle of the new test point is calculated to obtain the one-dimensional tilt angle of the new test point. This process is repeated to scan the wafer surface point by point.

[0074] Furthermore, the calculation process for the one-dimensional tilt angle is expressed as follows:

[0075]

[0076] Where θ represents a one-dimensional tilt angle, Z1 represents the distance data of the first measurement point from the ranging module, Z2 represents the distance data of the second measurement point from the ranging module, i represents the i-th measurement point, X1 represents the x-coordinate value of the first measurement point, and X2 represents the x-coordinate value of the second measurement point.

[0077] Figure 9 This is a schematic diagram of the wafer measurement system according to an embodiment of the present invention. Figure 9As shown, the wafer measurement system includes a light source module 100, a vacuum scattering tube 200, a detection module 300, and a wafer one-dimensional warp measurement device 400 as described in one of the above embodiments.

[0078] The wafer one-dimensional warp measurement device 400 includes a first motion platform 1, an image acquisition device 2, a ranging module 3, and a controller (not shown in the figure).

[0079] The light source module 100 emits X-rays that pass through the vacuum scattering tube 200 and irradiate the test point on the wafer on the first motion platform 1.

[0080] The controller is used to calculate the one-dimensional tilt angle of the point to be measured along the line connecting the projection points of the two measurement points on the vertical plane based on the distance data of the two measurement points uploaded by the ranging module 3, and then control the first motion platform 1 to rotate according to the one-dimensional tilt angle to perform surface tilt angle compensation.

[0081] The detection module 300 is used to acquire the scattered image formed by X-ray irradiation of the test point on the wafer after tilt compensation.

[0082] It should be noted that this wafer measurement system is based on CD-SAXS measurement technology. CD-SAXS measurement technology relies on iterative model fitting to solve the scattered signals from different incident angles on the wafer. To ensure accurate measurement results, CD-SAXS measurement technology has strict requirements on the incident angle of X-rays irradiating the measured point on the wafer. Therefore, in this embodiment, it is necessary to accurately measure the tilt angle caused by wafer warping, and then perform tilt angle compensation correction during the CD-SAXS measurement process to ensure that the incident angle of X-rays irradiating the warped part of the wafer meets the requirements.

[0083] Specifically, the first motion platform 1 is a six-degree-of-freedom motion platform, including three translational axes and three rotational degrees of freedom. In this embodiment, after the one-dimensional tilt angle of the test point is measured by the wafer one-dimensional warp measurement device 400, the first motion platform 1 is controlled to rotate according to the one-dimensional tilt angle, so that the X-rays irradiating the test point after rotation meet the incident angle requirements. The one-dimensional tilt angle includes the tilt angle of the test point along the line connecting the projection points of the two measurement points on the vertical plane. During tilt angle compensation, a perpendicular line is drawn from the test point as the origin to the line connecting the projection points on the vertical plane. The first motion platform 1 is controlled to rotate around this perpendicular line to overcome the one-dimensional tilt angle. After compensating for the one-dimensional tilt angle, the light source module 100 is controlled to emit X-rays to irradiate the test point on the wafer, and the detection module 300 is controlled to acquire the scattered image formed by the X-rays irradiating the test point on the wafer after tilt angle compensation.

[0084] The wafer measurement system in this embodiment uses a one-dimensional wafer warpage measurement device 400 to measure the one-dimensional tilt angle of the test point on the wafer. Then, it compensates for the one-dimensional tilt angle of the test point based on the measurement results, and then performs CD-SAXS measurement on the compensated test point. This ensures that the incident angle of the X-rays irradiating the test point meets the requirements, avoids inaccurate CD-SAXS measurement results due to wafer surface warpage, and greatly improves the accuracy of CD-SAXS measurement.

[0085] Furthermore, based on the above embodiments, in other embodiments, such as Figure 9 and Figure 10 As shown, the wafer one-dimensional warpage measurement device 400 also includes a second motion platform 6, on which the image acquisition device 2 and the ranging module 3 are mounted. The controller is also used to, before measuring the wafer, control the second motion platform 6 to move the image acquisition device 2 and the ranging module 3 from a preset standby position to a preset measurement position to measure and compensate for the one-dimensional tilt angle of the point to be measured, and then move the image acquisition device 2 and the ranging module 3 back from the preset measurement position to the preset standby position.

[0086] Specifically, in this embodiment, the image acquisition device 2 and the ranging module 3 are mounted on the second motion platform 6, which moves the image acquisition device 2 and the ranging module 3. When a one-dimensional tilt angle measurement is required, the controller controls the second motion platform 6 to move, causing the image acquisition device 2 and the ranging module 3 to move from a preset standby position to a preset measurement position. Then, the image acquisition device 2 and the ranging module 3 begin to work, measuring the one-dimensional tilt angle of the point to be measured. After the measurement is completed, the controller controls the second motion platform 6 to move again, causing the image acquisition device 2 and the ranging module 3 to move from the preset measurement position to the preset standby position, thus avoiding X-ray obstruction.

[0087] In this embodiment, the measurement steps of the wafer measurement system specifically include:

[0088] 1. The controller controls the second motion platform 6 to move the image acquisition device 2 and the ranging module 3 from the preset standby position to the preset measurement position.

[0089] 2. The image acquisition device 2 captures a surface image of the wafer on the first motion platform 1 and sends it to the controller.

[0090] 3. The controller identifies the test point based on a visual algorithm and determines the coordinate position of the test point.

[0091] 4. The controller drives the first motion platform 1 until the point to be measured coincides with the midpoint of the line connecting the two measurement points on the wafer surface of the ranging module 3.

[0092] 5. The distance measurement module 3 reads the distance data between the two measurement points and uploads the distance data to the controller.

[0093] 6. The controller calculates the one-dimensional tilt angle of the point to be measured based on the distance data.

[0094] 7. The controller controls the first motion platform 1 to rotate according to the one-dimensional tilt angle to compensate for the one-dimensional tilt angle, and at the same time controls the second motion platform 6 to move the image acquisition device 2 and the ranging module 3 from the preset measurement position to the preset standby position.

[0095] 8. The controller controls the light source module 100 to emit X-rays that irradiate the test points on the wafer.

[0096] 9. The detection module 300 acquires the scattered image formed by X-ray irradiation of the test point on the wafer after tilt compensation.

[0097] Based on the above steps, the wafer measurement system of this embodiment can complete the measurement of one test point on the wafer. However, when there are multiple test points, the above steps need to be executed multiple times to complete the measurement of multiple test points.

[0098] It should be noted that the ranging module 3 needs to form two measurement points, thus it has two rangefinders. When measuring multiple points, the two rangefinders need to move repeatedly between the standby position and the measurement position, which will generate displacement errors during this repeated movement. Specifically, in the CD-SAXS measurement process, due to the uncertainty of the displacement distance of the motion platform, that is, when the motion platform moves from one position to another, it cannot be guaranteed that the position will be completely coincident each time. There are certain displacement errors [ΔX, ΔY] in the X and Y axis directions. In addition, due to the spontaneous jitter effect of the motion platform, a height measurement error ΔZ is caused in the Z direction. That is, for a point on the wafer plane, when the two measuring instruments are not fixed together, each measuring instrument moves independently, and there will be an error during the movement, thus generating measurement errors [ΔX, ΔY, ΔZ] in three axes. 1,2,3 When there are N points to be measured, 2N measurements are required, resulting in 6N measurement errors. However, if the two measuring instruments are moved in parallel and fixed positions, their relative positions remain unchanged. Therefore, each measurement only involves one movement and generates only one set of errors [ΔX, ΔY, ΔZ]. For multiple points, the accumulated error is significantly reduced. Therefore, in this embodiment, the two rangefinders of the ranging module 3 are fixedly mounted on the second motion platform 6. The second motion platform 6 drives the two rangefinders to move synchronously, greatly reducing the accumulation of errors and improving the overall measurement accuracy.

[0099] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A wafer one-dimensional warpage measurement apparatus, characterized by comprising: It comprises: A first motion platform for carrying a wafer to be measured; An image acquisition device for shooting a wafer surface image and positioning a point to be measured on the wafer according to the image; A distance measuring module for forming two measuring points on the wafer surface, the distance measuring module for acquiring distance data between the distance measuring module and the two measuring points; A controller electrically connected with the first motion platform, the image acquisition device and the distance measuring module, for controlling the first motion platform to move according to the point to be measured positioned by the image acquisition device, so that the point to be measured coincides with the midpoint of the line connecting the two measuring points, then reading the distance data uploaded by the distance measuring module, and calculating a one-dimensional inclination of the point to be measured along the line connecting the projection points of the two measuring points on a vertical plane.

2. The wafer one-dimensional warpage measurement apparatus according to claim 1, wherein The distance measuring module comprises two spectral confocal range finders or two laser interference range finders.

3. The wafer one-dimensional warpage measurement apparatus according to claim 1, wherein The first motion platform is further provided with a visual standard sample for calibrating the relative spatial positions of the image acquisition device and the distance measuring module, so as to determine the relative position relationship between the field of view center of the image acquisition device and the midpoint of the line connecting the two measuring points. The controller is further used to control the first motion platform to move, so that the point to be measured coincides with the field of view center, and then drive the first motion platform to move according to the relative position relationship, so that the point to be measured coincides with the midpoint of the line connecting the two measuring points.

4. The wafer one-dimensional warpage measurement apparatus of claim 1, wherein The distance data of the distance measuring module from two measuring points is represented as H i (Z1,Z2), wherein Z1 represents distance data of a first measuring point from the distance measuring module, Z2 represents distance data of a second measuring point from the distance measuring module, and i represents the i-th measuring point; The calculation process of the one-dimensional inclination is represented as: Wherein, θ represents the one-dimensional inclination, X1 represents the horizontal coordinate value of the first measuring point, and X2 represents the horizontal coordinate value of the second measuring point.

5. The wafer one-dimensional warpage measurement apparatus of claim 1, wherein It further comprises a second motion platform, the image acquisition device and the distance measuring module are arranged on the second motion platform, and the second motion platform is used to drive the image acquisition device and the distance measuring module to move between a preset standby position and a preset measuring position.

6. A method for measuring the degree of one-dimensional warpage of a wafer, characterized by, It is applied to the wafer one-dimensional warping degree measuring device of any one of claims 1-5, the wafer one-dimensional warping degree measuring device comprising a first motion platform, an image acquisition device, a distance measuring module and a controller; the method comprises: The image acquisition device shoots a wafer surface image on the first motion platform and sends it to the controller; The controller identifies a point to be measured based on a visual algorithm and determines the coordinate position of the point to be measured; The controller drives the first motion platform until the point to be measured coincides with the midpoint of the line connecting the two measuring points of the distance measuring module on the wafer surface; The distance measuring module reads the distance data between the distance measuring module and the two measuring points and uploads the distance data to the controller; The controller calculates a one-dimensional inclination of the point to be measured along the line connecting the projection points of the two measuring points on a vertical plane based on the distance data.

7. The method of claim 6, wherein the one-dimensional wafer bow measurement method is characterized by, After the controller calculates a one-dimensional inclination of the point to be measured along the line connecting the projection points of the two measuring points on a vertical plane based on the distance data, it further comprises: The controller periodically drives the first moving platform to move by a preset step length, so that the midpoint of the line connecting the two measuring points moves to a new to-be-measured point, and distance data corresponding to the new to-be-measured point collected by the distance measuring module is acquired each time the new to-be-measured point is moved to, and a one-dimensional inclination of the new to-be-measured point in the direction of the line connecting the two measuring points in the vertical plane is calculated according to the distance data corresponding to the new to-be-measured point.

8. The method of claim 6, wherein the one-dimensional wafer bow measurement method is characterized by, The calculation process of the one-dimensional inclination is represented as: Wherein, θ represents the one-dimensional inclination, Z1 represents distance data of the first measuring point from the distance measuring module, Z2 represents distance data of the second measuring point from the distance measuring module, i represents the ith to-be-measured point, X1 represents a horizontal coordinate value of the first measuring point, and X2 represents a horizontal coordinate value of the second measuring point.

9. A wafer measurement system, characterized by, The wafer one-dimensional warping degree measurement device comprises a light source module, a vacuum scattering tube, a detection module, and the wafer one-dimensional warping degree measurement device according to any one of claims 1-5, the wafer one-dimensional warping degree measurement device comprising a first moving platform, an image acquisition device, a distance measuring module, and a controller, X-ray emitted by the light source module passes through the vacuum scattering tube and irradiates a to-be-measured point of a wafer on the first moving platform, the controller calculates a one-dimensional inclination of the to-be-measured point in the direction of the line connecting two measuring points in a vertical plane according to distance data corresponding to the two measuring points uploaded by the distance measuring module, the controller controls the first moving platform to rotate for surface inclination compensation according to the one-dimensional inclination, and the detection module is used to acquire a scattering image formed by X-ray irradiating the to-be-measured point of the wafer after inclination compensation.

10. The wafer measurement system of claim 9, wherein, The wafer one-dimensional warping degree measurement device further comprises a second moving platform, and the image acquisition device and the distance measuring module are arranged on the second moving platform. The controller is further configured to control the second moving platform to drive the image acquisition device and the distance measuring module to move from a preset standby position to a preset measurement position to measure the one-dimensional inclination of the to-be-measured point and perform inclination compensation before measuring the wafer, and then drive the image acquisition device and the distance measuring module to move from the preset measurement position back to the preset standby position.

Images