Measuring device monitoring apparatus, monitoring adjustment method and thickness measurement method, terminal and medium

Abstract

The application provides a measuring equipment monitoring device, a monitoring adjustment method, a thickness measurement method, a terminal and a medium, wherein the measuring equipment monitoring method comprises a repeatedly executed monitoring adjustment process; a single monitoring adjustment process comprises: measuring a reference wafer by a measuring equipment to obtain a monitoring data set; comparing the monitoring data set with a reference data set to obtain a difference condition; if the difference condition between the thickness monitoring data and the thickness reference data meets a thickness imbalance condition, performing alignment positioning adjustment on the measuring equipment; and if the difference condition between the warping monitoring data and the warping reference data meets a horizontal imbalance condition, performing horizontal adjustment on the measuring equipment. Through the repeatedly executed monitoring adjustment process, the state of the measuring equipment is monitored and maintained, the error of the measuring equipment is prevented from being too large, and the measurement accuracy of the measuring equipment is improved.

Description

Technical Field

[0001] This application belongs to the semiconductor field and relates to a wafer thickness measurement technology, particularly to a measurement equipment monitoring device, a monitoring and adjustment method, a thickness measurement method, a terminal, and a medium. Background Technology

[0002] In the back-end processes of wafer fabrication, the wafer substrate needs to be thinned to reduce wafer volume, meet miniaturization requirements, and lower on-resistance and thermal resistance. The substrate thickness has a significant impact on wafer performance. For example, for IGBT (Insulated Gate Bipolar Transistor) devices, the thickness of the silicon substrate affects the device's electrical and thermal performance. Generally, the thinned silicon substrate thickness needs to be around 100 μm. Therefore, it is necessary to measure the thickness of the thinned wafer substrate to ensure that its performance parameters meet design requirements.

[0003] Currently, wafer substrate thickness measurement is typically achieved using infrared interferometry. Specifically, such as... Figure 1 As shown, infrared light is incident perpendicularly onto a wafer substrate and reflected from both the upper and lower surfaces. The two reflected beams interfere, and the substrate thickness can be determined by detecting the intensity of the reflected light after interference. However, after the instrument has been in place for a long time, system drift errors can occur, potentially leading to inaccurate wafer thickness measurements or poor repeatability of multiple measurements at the same point on the substrate, thus making it impossible to obtain the substrate thickness. For example, as... Figure 2 As shown, the line graph on the left illustrates the results of five measurements of substrate thickness at nine measurement points on wafers A and B under test, respectively. The right side shows the distribution of these nine test points on the wafer under test. The test points within the green boxes represent points with good repeatability where the differences between the five measurements are within the normal fluctuation range, and can be considered valid test results. The test points within the red boxes represent points with excessively large differences between the five measurements, indicating poor repeatability and are considered invalid test results. This results in the inability to obtain the substrate thickness of the wafer or a large error in the measured wafer thickness. Furthermore, the fabricated wafers typically exhibit some warpage, which also affects the accuracy of the wafer substrate thickness measurement. Summary of the Invention

[0004] The purpose of this application is to provide a measuring equipment monitoring device, a monitoring and adjustment method, a thickness measurement method, a terminal, and a medium to solve the problem that measuring equipment left idle for a long time will produce large errors and have low measurement accuracy in the prior art.

[0005] In a first aspect, this application provides a measurement equipment monitoring device for monitoring and maintaining a measurement equipment used to measure the thickness of a wafer substrate. A reference wafer is mounted on the measurement equipment. The measurement equipment monitoring device includes a data acquisition module, a comparison module, and an adjustment module that repeatedly executes a monitoring and adjustment process. The data acquisition module is used to acquire a monitoring data set by measuring the reference wafer through the measurement equipment. The monitoring data set includes thickness monitoring data and warpage monitoring data. The comparison module is used to compare the monitoring data set with the reference data set to obtain the differences. The reference data set includes thickness reference data and warpage reference data. The reference data set is used to characterize the thickness and warpage of the reference wafer when the measurement equipment is in a standard measurement state. The adjustment module is used to perform alignment and positioning adjustments on the measurement equipment when the difference between the thickness monitoring data and the thickness reference data meets a thickness imbalance condition; and to perform horizontal adjustments on the measurement equipment when the difference between the warpage monitoring data and the warpage reference data meets a horizontal imbalance condition.

[0006] Secondly, this application provides a method for monitoring a measuring device, used to monitor and maintain the measuring device, which is used to measure the thickness of a wafer substrate. A reference wafer is mounted on the measuring device. The method includes a repetitive monitoring and adjustment process. Each monitoring and adjustment process includes: measuring the reference wafer using the measuring device to obtain a set of monitoring data; the set of monitoring data includes thickness monitoring data and warpage monitoring data; comparing the set of monitoring data with a reference data set to obtain differences; the reference data set includes thickness reference data and warpage reference data; the reference data set is used to characterize the thickness and warpage of the reference wafer when the measuring device is in a standard measurement state; if the difference between the thickness monitoring data and the thickness reference data satisfies a thickness imbalance condition, the measuring device is aligned and positioned; if the difference between the warpage monitoring data and the warpage reference data satisfies a horizontal imbalance condition, the measuring device is horizontally adjusted.

[0007] In one embodiment of this application, the method for obtaining the reference data includes: performing the alignment and positioning adjustment and the horizontal adjustment on the measuring device to adjust the measuring device to the standard measurement state; after the measuring device is in the standard measurement state, measuring the thickness reference data and the warpage reference data through the measuring device.

[0008] In one embodiment of this application, the measuring device employs interferometry for measurement and includes: a light output unit, a light detection unit, and a fixing unit; the alignment and positioning adjustment includes: turning on the light output unit to output a measurement beam, the measurement beam passing through the measurement optical path and then incident on the light detection unit to form a light spot; adjusting the light output unit and the measurement optical path so that the center of the light spot coincides with the center of the light detection unit, and the area of ​​the light spot is a preset area, and the light intensity of the light spot is a preset light intensity; acquiring the standard orientation mark of the reference wafer; rotating the reference wafer based on the standard orientation mark to initially adjust the mounting angle of the reference wafer; placing the initially adjusted reference wafer on the fixing unit and acquiring a contour image; and calculating the center offset degree and angle offset degree of the reference wafer based on the contour image, and then finely adjusting the reference wafer based on the center offset degree and angle offset degree.

[0009] In one embodiment of this application, the alignment and positioning adjustment, after fine adjustment of the reference wafer, further includes: obtaining the coordinate system direction of the reference wafer and the coordinate system direction of the fixed unit respectively, and confirming that the coordinate system direction of the reference wafer and the coordinate system direction of the fixed unit are consistent, so as to ensure that the coordinate systems of the reference wafer and the fixed unit coincide.

[0010] In one embodiment of this application, the measuring device further includes: a contour measuring unit; the fixing unit includes a plurality of fixing structures; the horizontal adjustment includes: adjusting the position of each fixing structure based on a preset position of each fixing structure to adjust the levelness of each fixing structure.

[0011] Thirdly, this application provides a thickness measurement method, in which the wafer to be measured is fixed to a measuring device, the measuring device is turned on, and initial thickness data and warpage data are obtained; based on the warpage data, the initial thickness data is corrected to obtain the thickness data of the wafer to be measured; wherein the measuring device is monitored and maintained based on the measuring device monitoring method described above.

[0012] In one embodiment of this application, the step of correcting the initial thickness data based on the warp data to obtain the thickness data of the wafer under test includes: obtaining the bevel angle of each preset measurement point of the wafer under test based on the warp data; and calculating the thickness value of each measurement point based on the bevel angle of each measurement point and the initial thickness data to obtain the thickness data of the wafer under test.

[0013] Fourthly, this application provides a terminal, including: a processor and a memory, wherein the memory and the processor are communicatively connected;

[0014] The memory is used to store computer programs, and the processor is used to execute the computer programs stored in the memory to enable the terminal to perform the measurement device monitoring method or thickness measurement method as described above.

[0015] Fifthly, this application provides a computer storage medium storing a computer program, which, when executed by a processor, implements the measurement device monitoring method or thickness measurement method as described above.

[0016] As described above, this application provides a measurement equipment monitoring device, a monitoring and adjustment method, a thickness measurement method, a terminal, and a medium. Through a repeated monitoring and adjustment process, the measurement equipment is monitored and maintained to obtain the current error status of the measurement equipment and to correct it when the error is too large, thereby improving the measurement accuracy of the measurement equipment. Moreover, the measurement equipment does not need to be recalibrated before use, which helps to reduce the operational difficulty of wafer substrate thickness measurement, improves measurement efficiency, and has high industrial application value. Attached Figure Description

[0017] Figure 1 This diagram illustrates the principle of measuring wafer substrate thickness using infrared interferometry.

[0018] Figure 2 This is a schematic diagram showing the results of measurements at various measurement points on the wafer under test in the prior art.

[0019] Figure 3 The diagram shown is a flowchart illustrating a single monitoring and adjustment process as described in an embodiment of this application.

[0020] Figure 4 The diagram shown is a structural schematic of a measuring device according to an embodiment of this application.

[0021] Figure 5 The diagram shows a schematic of the principle of obtaining thickness and warpage data using infrared interferometry.

[0022] Figure 6 The diagram shows a flowchart illustrating a method for acquiring reference data for a reference wafer as described in an embodiment of this application.

[0023] Figure 7 The diagram shown is a flowchart illustrating an alignment and positioning adjustment and a horizontal adjustment process as described in an embodiment of this application.

[0024] Figure 8 The diagram shown is a structural schematic of a fixed unit as described in an embodiment of this application.

[0025] Figure 9 The diagram shown is a flowchart illustrating a thickness measurement method according to an embodiment of this application.

[0026] Figure 10 This diagram illustrates the measurement points of a wafer under test as described in an embodiment of this application.

[0027] Figure 11 This diagram illustrates the measurement point setup for a wafer under test as described in an embodiment of this application.

[0028] Figure 12 The diagram shown is a flowchart illustrating an initial thickness data correction process as described in an embodiment of this application.

[0029] Figure 13 This is a schematic diagram showing the three-dimensional morphology data of a wafer surface obtained in an embodiment of this application.

[0030] Figure 14 The diagram shown is a structural schematic of a measuring equipment monitoring device according to an embodiment of this application.

[0031] Figure 15 The diagram shown is a structural schematic of a terminal as described in an embodiment of this application.

[0032] Explanation of reference numerals in the attached figures

[0033] 10: Optical output unit; 20: Optical detection unit; 30: Fixing unit; 31: Fixing structure; 40: Reflector; 50: Semi-transparent mirror; 61: Data acquisition module; 62: Comparison module; 63: Adjustment module; 70: Terminal; 71: Processor; 72: Memory; 721: Operating system; 722: Application program; 73: User interface; 74: Network interface; 75: Bus system. Detailed Implementation

[0034] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0035] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0036] Existing wafer substrate thickness measurement methods suffer from low accuracy due to system drift errors that occur after prolonged periods of inactivity. While calibrating the measurement equipment before each measurement can eliminate these drift errors and improve accuracy, the calibration process is cumbersome, making wafer substrate measurement difficult and inefficient.

[0037] To address the technical problems existing in the prior art, the following embodiments of this application provide a measurement equipment monitoring device, a monitoring and adjustment method, a thickness measurement method, a terminal, and a medium. Through a repeated monitoring and adjustment process, the measurement equipment is monitored and maintained, and correction is performed when the error of the measurement equipment is too large, so as to ensure the measurement accuracy of the measurement equipment. This results in high accuracy of the wafer substrate thickness measured by the measurement equipment, and the measurement equipment does not need to be recalibrated before measuring the wafer substrate thickness, effectively reducing the operational difficulty of wafer substrate thickness measurement and improving measurement efficiency.

[0038] The following embodiments of this application provide a measurement equipment monitoring device, a monitoring and adjustment method, a thickness measurement method, a terminal, and a medium, which are included but not limited to applications for measuring the substrate thickness, oxide layer thickness, metal layer thickness, or photoresist thickness of wafers. This application does not specifically limit these applications. The following description will use the measurement of wafer substrate thickness as an example.

[0039] The technical solutions in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0040] This embodiment provides a method for monitoring measuring equipment, used for monitoring and maintaining measuring equipment, such as the ONTO Element series Fourier transform infrared spectrometer. Specifically, the method includes a repetitive monitoring and adjustment process, wherein the time interval between two adjacent monitoring and adjustment processes is a preset time interval. For example, the preset time interval is 1 week or 3 days. Those skilled in the art can set the time interval between two adjacent monitoring and adjustment processes according to actual needs, and this embodiment does not impose specific limitations.

[0041] By monitoring and adjusting the measurement process repeatedly, the measurement error of the measuring equipment is monitored. When the error of the measuring equipment becomes too large, it is corrected in time, thereby ensuring the measurement accuracy of the measuring equipment. This also avoids the need to calibrate the measuring equipment every time a measurement is performed, which helps to reduce the operational complexity of the measurement process and improve measurement efficiency.

[0042] In some alternative implementations, such as Figure 3 As shown, a single monitoring and adjustment process includes:

[0043] The S100, based on a reference wafer, uses measurement equipment to acquire a set of monitoring data.

[0044] The measuring equipment is used to measure the thickness of the wafer substrate.

[0045] During the monitoring and adjustment process, a reference wafer is installed on the measuring equipment. The reference wafer is used to calibrate the current error of the measuring equipment by measuring the data from the reference wafer during the monitoring and adjustment process. Exemplarily, the reference wafer is a bare silicon wafer or a silicon wafer with a specific film deposited on it. Those skilled in the art should know that the reference wafer is selected based on actual needs, and this embodiment does not impose specific limitations.

[0046] The monitoring data set includes thickness monitoring data and warpage monitoring data. Thickness monitoring data characterizes the substrate thickness of the reference wafer measured by the current measurement equipment, while warpage monitoring data characterizes the tilt of the reference wafer measured by the current measurement equipment.

[0047] For example, preset measurement points are set on the reference wafer. The thickness monitoring data is the thickness at each measurement point measured by the current measuring device. The warpage monitoring data is the three-dimensional topography data of the reference wafer measured by the current measuring device, or the tangent slope at each measurement point measured by the current measuring device, to reflect the tilt of the current reference wafer.

[0048] In some alternative implementations, the measuring device employs interferometry for measurement. Specifically, such as... Figure 4 As shown, the measuring device includes a light output unit 10, a light detection unit 20, and a fixing unit 30. The light output unit 10 outputs a measurement beam, which is split into a reference beam and an object beam. For example, as... Figure 4 As shown, two reflected light beams are formed by reflections on the upper and lower surfaces of the reference wafer substrate, serving as a reference beam and an object beam, respectively, to reflect the substrate thickness of the wafer. The photodetector unit 20 receives the incident light spot after the two beams interfere, records the interference pattern, and transmits it to an external computer for analysis and calculation. The fixing unit 30 is used to fix the wafer; during monitoring and adjustment, the fixing unit 30 is used to fix the reference wafer. Exemplarily, the light output unit 10 is a laser source with an output wavelength range of 0.75-25µm, the photodetector unit 20 is a CCD camera, and the fixing unit 30 is a chuck including multiple vacuum chucks or electrostatic chucks.

[0049] It should be noted that when the measuring equipment measures the thickness monitoring data of the reference wafer, the measuring beam is incident on each measurement point of the reference wafer and reflected from the upper and lower surfaces of the wafer substrate. The resulting two reflected beams serve as the object beam and the reference beam, respectively. Figure 5 As shown by the red arrow, the two reflected beams interfere with each other to form an interference pattern, which is received by the photodetector unit 20 to analyze and obtain the thickness of each measurement point based on the interference pattern.

[0050] Furthermore, the measuring device also includes a contour measuring unit (not shown in the figure), used to measure and acquire the three-dimensional topographic data of the reference wafer fixed on the fixing unit 30 or the tangent slope at each measurement point, as warpage monitoring data of the reference wafer. Specifically, those skilled in the art should know the specific structure of the contour measuring unit and the specific methods and principles for acquiring warpage monitoring data; this embodiment does not impose specific limitations here.

[0051] Based on this, the thickness and tilt of the reference wafer obtained by the current measurement equipment are obtained to reflect whether the current measurement equipment is in a standard measurement state suitable for measuring the thickness of the wafer substrate.

[0052] S200 compares the monitoring data set with the baseline data set to obtain the differences.

[0053] The reference data set is used to characterize the thickness and warpage of the reference wafer when the measuring equipment is in standard measurement mode. Standard measurement mode refers to the state when the measuring equipment performs error-free measurements.

[0054] The reference data set includes thickness reference data and warpage reference data. Thickness reference data represents the substrate thickness obtained by measuring a reference wafer when the measuring equipment is in standard measurement mode. For example, the thickness reference data may be the thickness at each measurement point obtained when the measuring equipment is in standard measurement mode. Warpage reference data represents the tilt obtained by measuring a reference wafer when the measuring equipment is in standard measurement mode. For example, warpage reference data may be the three-dimensional topography data of the reference wafer obtained when the measuring equipment is in standard measurement mode, or the tangent slope at each measurement point obtained when the measuring equipment is in standard measurement mode.

[0055] Specifically, when the measuring equipment is in standard measurement mode, a reference wafer is measured to obtain thickness reference data and warpage reference data. It should be noted that in order to ensure that the measuring equipment is in standard measurement mode, it needs to be calibrated to eliminate any errors present in the measuring equipment, and error-free measurements are performed after calibration.

[0056] In some alternative implementations, such as Figure 6As shown, the methods for obtaining reference data for a reference wafer include:

[0057] S210, perform alignment and leveling adjustments on the measuring equipment to bring it to a standard measuring state.

[0058] Specifically, the calibration of the measuring equipment includes alignment and leveling adjustments to bring the measuring equipment to a standard measuring state and obtain reference data.

[0059] Alignment and positioning adjustment refers to aligning and positioning the positions of each structure to ensure that each structure is in the position required for standard measurement. For example, alignment and positioning adjustment includes aligning the light output unit 10 and the light detection unit 20, i.e., adjusting the positions of the light output unit 10 and the light detection unit 20 so that the formed interference pattern can be received by the light detection unit 20. Alignment and positioning adjustment also includes aligning the angle and position of the reference wafer so that its position on the fixing unit 30 is centered and the angle is a preset angle. Horizontal adjustment refers to adjusting the tilt of each structure to ensure that each structure is in a horizontal state. For example, horizontal adjustment includes adjusting the tilt of the fixing unit 30 to ensure that the reference wafer is in a horizontal state when fixed on the fixing unit 30.

[0060] To facilitate understanding by those skilled in the art, examples of alignment and positioning adjustment and horizontal adjustment are given below.

[0061] In some alternative implementations, such as Figure 7 As shown, the alignment and positioning adjustment includes:

[0062] S211, turn on the light output unit 10 to output the measurement beam. After passing through the measurement optical path, the measurement beam is incident on the light detection unit 20 to form a light spot. Adjust the light output unit 10 and the measurement optical path so that the center of the light spot coincides with the center of the light detection unit 20, and the area of ​​the light spot is a preset area and the light intensity of the light spot is a preset light intensity.

[0063] The measurement optical path refers to the optical path through which the measurement beam passes from the optical output unit 10 to the optical detection unit 20.

[0064] For example, when obtaining the thickness reference data of a reference wafer, please refer to... Figure 4The measurement optical path consists of a measurement beam emitted from the light output unit 10. This beam is reflected by the upper and lower surfaces of the reference wafer substrate, forming two beams. After interference, the two beams are reflected by the semi-transparent mirror 50 to the photodetector unit 20. Based on this, the light output unit 10 and the measurement optical path are adjusted so that the center of the light spot coincides with the center of the photodetector unit 20. This actually involves adjusting the position and angle of the light output unit 10 and the semi-transparent mirror 50 so that the center of the light spot received by the photodetector unit 20 coincides with the center of the photodetector unit 20. It should be noted that during the debugging of the measurement equipment, a reference wafer is usually not installed on the equipment for ease of operation. Therefore, to ensure that the measurement beam is reflected after incident on the reference wafer, a reflective element, such as a reflective mirror, can be placed at the location of the reference wafer.

[0065] Furthermore, the light output unit 10 is adjusted to adjust the area of ​​the light spot to a preset area, and the light intensity of the light spot is a preset light intensity. Those skilled in the art should know that the preset area and preset light intensity can be specifically set based on actual needs; this embodiment does not impose specific limitations here. For example, the light spot area is the area of ​​a circle with a diameter of 40 micrometers, and the preset light intensity is 15000 counts. Here, counts is the digital unit of the light detection unit 20, meaning that the light detection unit 20 receives the light signal and converts it into an electrical signal through photoelectric conversion. After analog-to-digital conversion, the light intensity reaching a minimum digital increment is 1 count. The preset light intensity of 15000 counts means that within a single exposure time, the digital increment output after receiving the light spot by the light detection unit 20 is 15000.

[0066] S212, acquire the standard orientation mark of the reference wafer; based on the standard orientation mark, rotate the reference wafer to perform initial adjustment of the wafer mounting angle; place the initially adjusted reference wafer on the fixed unit 30 and acquire the contour image; based on the contour image, calculate the center offset degree and angle offset degree of the reference wafer respectively, and perform fine adjustment of the reference wafer based on the center offset degree and angle offset degree.

[0067] The standard orientation mark on the reference wafer is used to identify the crystallographic orientation of the wafer, ensuring that subsequent wafer processing or measurement is based on a specific crystallographic orientation, thus guaranteeing the consistency of device performance. For example, the standard orientation mark is a notch or flat edge on the wafer edge.

[0068] It should be noted that the fixing unit 30 typically has specific requirements for the orientation of the standard orientation mark on the wafer. For example, the standard orientation mark on the reference wafer should face the side of the operator to ensure that the reference wafer fixed on the fixing unit 30 is processed according to a specific crystallographic orientation during subsequent measurements. Based on this, in this embodiment, rotating the standard orientation mark on the reference wafer to match the orientation marked on the fixing unit 30 can achieve alignment of the wafer's mounting angle.

[0069] Based on this, a reference wafer is obtained, and the reference wafer is rotated according to the standard orientation mark to make the orientation of the reference wafer consistent with the orientation requirement marked on the fixing unit 30. The rotated reference wafer is then translated and placed on the fixing unit 30 to achieve the initial adjustment of the reference wafer.

[0070] Furthermore, after the reference wafer is translated and placed onto the fixed unit 30, images of the reference wafer and the fixed unit 30 are acquired as contour images. Based on the contour images, edge recognition algorithms, such as the Sobel operator, the Canny algorithm, or deep learning-based edge detection algorithms, are used to extract the edge contours of the reference wafer and the fixed unit 30, respectively. Thus, based on the edge contours of the reference wafer and the fixed unit 30, the positions of the standard orientation mark on the reference wafer and the mark on the fixed unit 30 are obtained. Based on the positions of the standard orientation mark on the reference wafer and the mark on the fixed unit 30, the degree of angular offset of the reference wafer is analyzed. Based on the degree of angular offset, the reference wafer is rotated again, thereby achieving fine adjustment of the wafer mounting angle.

[0071] It should be noted that during the positioning of the reference wafer, it is also necessary to ensure that the reference wafer is located at the center of the fixed unit 30, that is, the center of the reference wafer coincides with the center of the fixed unit 30, to ensure that no offset occurs when the measurement beam is incident on each measurement point of the reference wafer. Based on this, after obtaining the edge contours of the reference wafer and the fixed unit 30, the center positions of the reference wafer and the fixed unit 30 are obtained based on the edge contours of the reference wafer and the fixed unit 30. Then, based on the center positions of the reference wafer and the fixed unit 30, the degree of center offset of the reference wafer is analyzed, and the reference wafer is translated based on the degree of center offset, thereby ensuring that the reference wafer is located at the center of the fixed unit 30.

[0072] It is worth noting that the above steps of obtaining the center offset and angular offset of the reference wafer, and then finely adjusting the reference wafer based on the center offset and angular offset, are not limited in their order. In actual implementation, those skilled in the art can first rotate the reference wafer based on the angular offset, and then translate the reference wafer based on the center offset, or they can first translate the reference wafer based on the center offset, and then rotate the reference wafer based on the angular offset. This embodiment does not impose any specific limitations here.

[0073] Furthermore, to ensure the crystallographic orientation of the wafer is in a specific direction and to avoid the reference wafer and the fixed unit 30 having opposite directions, after fine-tuning the reference wafer, the method further includes: acquiring the coordinate system orientation of the reference wafer and the coordinate system orientation of the fixed unit 30 respectively, and confirming that the coordinate system orientations of the reference wafer and the fixed unit 30 are consistent to ensure that the coordinate systems of the reference wafer and the fixed unit 30 coincide. The coordinate system of the reference wafer is generally, when the standard orientation mark is facing the worker, with the center of the reference wafer as the origin, the positive X-axis horizontally to the right, and the positive Y-axis vertically upward; the coordinate system of the fixed unit 30 is generally, a right-hand rectangular three-dimensional coordinate system with the mechanical center of the fixed unit 30 as the origin, and the direction of horizontal platform movement as the x-axis. That is, in practice, when the standard orientation mark is facing the worker, it is confirmed whether the horizontal movement of the platform is to the right. Those skilled in the art should know the specific setting methods of the reference wafer coordinate system and the fixed unit 30 coordinate system; this embodiment does not specifically limit them.

[0074] In some alternative implementations, such as Figure 7 As shown, the horizontal adjustment includes:

[0075] S213, based on the preset positions of each fixed structure 31, adjust the position of each fixed structure 31 to adjust the levelness of each fixed structure 31.

[0076] Each fixing structure 31 is a structure in the fixing unit 30 used to fix the position of the reference wafer, so as to prevent the reference wafer from moving during subsequent measurement and causing inaccurate measurement results. The fixing unit 30 includes multiple fixing structures 31, for example, such as Figure 8 As shown, the fixing unit 30 includes six uniformly distributed vacuum chucks or electrostatic chucks.

[0077] To ensure that the reference wafer is placed horizontally on the fixing unit 30, the position of each fixing structure 31 needs to be adjusted so that the height of each fixing structure 31 is consistent.

[0078] Specifically, each fixing structure 31 has a preset position. By adjusting each fixing structure 31 to its preset position, the height of each fixing structure 31 can be kept consistent.

[0079] It should be noted that those skilled in the art should know the specific execution methods and principles for adjusting each fixed structure 31 to its preset position, and this embodiment does not make specific limitations here.

[0080] Furthermore, when adjusting the position of each fixing structure 31, if a fixing structure 31 cannot be adjusted to its preset position, then the fixing structure 31 is damaged. Replace the fixing structure 31 and readjust it to the preset position.

[0081] It should be noted that during the position adjustment of each fixed structure 31, the reference wafer is usually removed for adjustment in order to facilitate operation.

[0082] It should be noted that steps S211, S212, and S213 are merely for ease of understanding and to categorize and label the different steps; they do not represent the execution order of the steps. In practice, since steps S211 and S213 both require removing the reference wafer, and step S212 is actually the step of placing the reference wafer onto the fixed unit 30, steps S211 and S213 are usually executed first, followed by step S212. For example, in actual implementation, those skilled in the art adjust the measuring equipment to the standard measuring state in the order of steps S211, S213, and S212; or, those skilled in the art adjust the measuring equipment to the standard measuring state in the order of steps S213, S211, and S212.

[0083] S220: After the measuring equipment is in the standard measuring state, the thickness reference data and warpage reference data are obtained by measuring the equipment.

[0084] Specifically, the thickness at each measurement point of the reference wafer is obtained as thickness reference data, and the three-dimensional topography data of the reference wafer, or the tangent slope at each measurement point, is obtained as warpage reference data.

[0085] For example, the measuring device uses interferometry to measure and obtain thickness reference data, and uses a contour measurement unit to obtain warpage reference data. Specifically, the methods for obtaining thickness reference data and warpage reference data are described in the foregoing methods for obtaining thickness monitoring data and warpage monitoring data, and will not be repeated here in this embodiment.

[0086] S300: If the difference between the thickness monitoring data and the thickness reference data meets the thickness imbalance condition, the measuring equipment is aligned and positioned; if the difference between the warp monitoring data and the warp reference data meets the horizontal imbalance condition, the measuring equipment is leveled.

[0087] Among them, the thickness imbalance condition is used to characterize the difference between the thickness monitoring data and the thickness reference data when the measuring equipment is not in the standard measuring state; the horizontal imbalance condition is used to characterize the difference between the warpage monitoring data and the warpage reference data when the measuring equipment is not in the standard measuring state.

[0088] It should be noted that when the thickness imbalance condition is met, there is a drift error in the alignment between the reference wafer and the measuring device. Based on this, alignment and positioning adjustment is performed, i.e., steps S211 and S212 are executed. When the horizontal imbalance condition is met, the reference wafer is tilted, and there is a drift error in the horizontal situation. Based on this, horizontal adjustment is performed, i.e., step S213 is executed.

[0089] In some optional implementations, the thickness monitoring data refers to the thickness at each measurement point measured by the current measuring device, the thickness reference data refers to the thickness at each measurement point measured when the measuring device is in standard measurement mode, and the thickness imbalance condition is that the difference between the thickness at any measurement point in the thickness monitoring data and the thickness in the thickness reference data does not exceed a thickness difference threshold. Those skilled in the art should understand that the thickness difference threshold can be specifically set based on actual needs; this embodiment does not impose specific limitations. For example, the thickness difference threshold is 10µm.

[0090] Similarly, the warpage monitoring data consists of the tangent slope at each measurement point measured by the current measuring device, the warpage reference data consists of the tangent slope at each measurement point measured when the measuring device is in standard measurement mode, and the horizontal imbalance condition is that the difference between the tangent slope at any measurement point in the warpage monitoring data and the tangent slope in the warpage reference data does not exceed a slope difference threshold. Those skilled in the art should understand that the slope difference threshold can be specifically set based on actual needs; this embodiment does not impose specific limitations. For example, the slope difference threshold is 1.

[0091] Based on this, by repeatedly performing the monitoring and adjustment process, the measuring equipment is ensured to be in the standard measuring state. When the measuring equipment deviates from the standard measuring state, alignment and horizontal adjustment are performed to restore the measuring equipment to the standard measuring state, thereby eliminating the error of the measuring equipment, improving the measurement accuracy of the measuring equipment, and the measuring equipment does not need to be recalibrated before each measurement, effectively improving the efficiency of wafer substrate thickness measurement.

[0092] This embodiment provides a thickness measurement method applied to a measurement device using the monitoring method described above, to measure the thickness at various measurement points on a wafer under test. Specifically, this method is used to ensure the accuracy of substrate thickness measurement in case of wafer warpage.

[0093] Specifically, such as Figure 9 As shown, the thickness measurement methods include:

[0094] S10: Fix the wafer to be tested to the measuring device, turn on the measuring device, and obtain the initial thickness data and warpage data.

[0095] The initial thickness data refers to the thickness of the wafer at each measurement point in the vertical direction. Specifically, the set of thickness values ​​at each measurement point in the vertical direction is used as the initial thickness data. Please refer to [reference needed]. Figure 10 In this figure, the blue square represents a part of the wafer to be measured. The thickness value of measurement point a in the vertical direction is the length of the yellow dashed line in the blue square.

[0096] Warpage data refers to the warpage of the wafer surface under test. For example, warpage data can be the three-dimensional topography data of the wafer surface under test, or the tangent slope at each measurement point of the wafer under test. Specifically, for the method of obtaining warpage data, please refer to the aforementioned method of obtaining warpage monitoring data; this embodiment will not repeat it here.

[0097] It should be noted that when performing thickness measurements after wafer substrate thinning, circuit structures are usually already formed on the wafer. To avoid the influence of these circuit structures on the wafer substrate thickness measurement, the areas without circuit structures are typically selected as the measurement points. For example, please refer to... Figure 11 Among them, measurement points 1, 2, 3 and 4 are all located in the section without a wire structure.

[0098] S20, based on warpage data, corrects the initial thickness data to obtain the thickness data of the wafer under test.

[0099] Specifically, such as Figure 10 As shown, taking measurement point a as an example, the actual thickness of the wafer to be measured should be the length h of the green dashed line within the blue square.

[0100] Based on this, the initial thickness data is corrected according to the warpage of the wafer under test. Specifically, such as... Figure 12 As shown, the correction process for the initial thickness data includes:

[0101] S21, based on the warp data, obtain the slant angle of each preset measurement point on the wafer under test.

[0102] Specifically, if the warpage data is the three-dimensional topography data of the wafer surface to be measured, the tangent slope at each measurement point is calculated based on this three-dimensional topography data, and the corresponding shear angle is calculated based on the tangent slope. For example, such as... Figure 13The figure shows the three-dimensional topographic data of the wafer surface to be measured. Based on the three-dimensional topographic data, the wafer surface to be measured is fitted into an ideal dome, and based on the surface equation of the ideal dome, the tangent slope of each measurement point is obtained.

[0103] If the warpage data is the tangent slope of each measurement point on the wafer under test, then the corresponding tangent angle is calculated based on the tangent slope.

[0104] For example, based on the tangent slope of each measurement point, the corresponding oblique angle is calculated as follows:

[0105]

[0106] in, It is the oblique angle. is the slope of the tangent line.

[0107] S22, based on the oblique cutting angle of each measurement point and combined with the initial thickness data, calculates the thickness value of each measurement point to obtain the thickness data of the wafer to be measured.

[0108] Specifically, please see Figure 10 The actual thickness of the wafer under test and its vertical thickness form a right triangle, and the oblique cutting angle is one angle of this triangle. Based on this, the actual thickness of the wafer under test is calculated as follows:

[0109]

[0110] in, This is the actual thickness. The measured vertical thickness.

[0111] Based on this, by correcting the initial thickness data using warpage data, accurate wafer substrate thickness data can be obtained, avoiding the impact of wafer warpage on thickness measurement and improving the accuracy of wafer thickness measurement.

[0112] like Figure 14 As shown, this embodiment provides a measurement equipment monitoring device, including a data acquisition module 61, a comparison module 62, and an adjustment module 63.

[0113] The data acquisition module 61 is used to acquire a monitoring data set by measuring a reference wafer using a measuring device; the monitoring data set includes thickness monitoring data and warpage monitoring data.

[0114] The comparison module 62 is used to compare the monitoring data set with the reference data set to obtain the differences; the reference data set includes thickness reference data and warpage reference data; the reference data set is used to characterize the thickness and warpage of the reference wafer when the measuring equipment is in standard measurement state.

[0115] The adjustment module 63 is used to adjust the alignment and positioning of the measuring device when the difference between the thickness monitoring data and the thickness reference data meets the thickness imbalance condition; and to adjust the level of the measuring device when the difference between the warp monitoring data and the warp reference data meets the horizontal imbalance condition.

[0116] Based on the same technical concept, the measurement equipment monitoring method or thickness measurement method provided in the embodiments of the present invention can be implemented on the terminal side or the server side.

[0117] like Figure 15 The diagram illustrates an optional hardware structure of a terminal according to an embodiment of the present invention. The terminal 70 can be a mobile phone, computer device, tablet device, personal digital processing device, factory back-end processing device, etc. The terminal 70 includes at least one processor 71, a memory 72, at least one network interface 74, and a user interface 73. The various components in the device are coupled together via a bus system 75. It is understood that the bus system 75 is used to realize communication between these components. In addition to a data bus, the bus system 75 also includes a power bus, a control bus, and a status signal bus.

[0118] The user interface 73 may include a monitor, keyboard, mouse, trackball, clicker, button, touchpad, or touch screen.

[0119] It is understood that memory 72 can be volatile memory or non-volatile memory, or both. Non-volatile memory can be read-only memory (ROM) or programmable read-only memory (PROM), used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM) and synchronous static random access memory (SSRAM). The memory characterized in the embodiments of the present invention is intended to include, but is not limited to, these and any other suitable categories of memory.

[0120] In this embodiment of the invention, the memory 72 is used to store various types of data to support the operation of the terminal. Examples of this data include: any executable program for operation on the terminal 70, such as the operating system 721 and application programs 722; the operating system 721 contains various system programs, such as the framework layer, core library layer, driver layer, etc., for implementing various basic services and handling hardware-based tasks. The application program 722 may contain various applications, such as media players, browsers, etc., for implementing various application services. The measurement device monitoring method or thickness measurement method provided in this embodiment of the invention may be included in the application program 722.

[0121] The methods disclosed in the above embodiments of the present invention can be applied to processor 71, or implemented by processor 71. Processor 71 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the integrated logic circuit of the hardware in processor 71 or by instructions in the form of software. The processor mentioned above may be a general-purpose processor, a digital signal processor (DSP), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. Processor 71 can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present invention. Processor 71 may be a microprocessor or any conventional processor, etc. The steps of the accessory optimization method provided in the embodiments of the present invention can be directly reflected as being executed by a hardware decoding processor, or being executed by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium, which is located in a memory. The processor reads the information in the memory and combines it with its hardware to complete the steps of the aforementioned method.

[0122] In an exemplary embodiment, terminal 70 may be used by one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), or complex programmable logic devices (CPLDs) to execute the aforementioned method.

[0123] This invention also provides a computer-readable storage medium storing a computer program that, when invoked by a processor, implements the measurement device monitoring method or thickness measurement method provided by this invention.

[0124] A computer-readable storage medium can be a tangible device capable of holding and storing instructions used by an instruction execution device. Computer-readable storage media can be, for example, (but not limited to) electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, and mechanical encoding devices.

[0125] The computer-readable program represented herein can be downloaded from a computer-readable storage medium to various computing / processing devices, or downloaded via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network, to an external computer or external storage device. A network adapter card or network interface in each computing / processing device receives computer-readable program instructions from the network and forwards these instructions to the computer-readable storage medium in the respective computing / processing device.

[0126] In summary, this application monitors the error of the measuring equipment through a repeated monitoring and adjustment process, and corrects the error when it becomes too large. This not only improves the measurement accuracy of the measuring equipment, but also eliminates the need to recalibrate the measuring equipment before measurement, thus improving measurement efficiency.

[0127] The descriptions of the processes or structures corresponding to the above figures each have their own emphasis. For parts of a process or structure that are not described in detail, please refer to the relevant descriptions of other processes or structures.

[0128] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A measuring equipment monitoring device for monitoring and maintaining measuring equipment, said measuring equipment being used to measure the thickness of a wafer substrate, wherein a reference wafer is mounted on the measuring equipment, characterized in that... It includes a data acquisition module, a comparison module, and a regulation module that repeatedly execute the monitoring and adjustment process; The data acquisition module is used to perform measurements based on the reference wafer using the measuring device to acquire a monitoring data set; the monitoring data set includes thickness monitoring data and warpage monitoring data. The comparison module is used to compare the monitoring data set with the reference data set to obtain the differences; the reference data set includes thickness reference data and warpage reference data. The reference data set is used to characterize the thickness and warpage of the reference wafer when the measuring device is in a standard measuring state; The adjustment module is used to perform alignment and positioning adjustment on the measuring device when the difference between the thickness monitoring data and the thickness reference data meets the thickness imbalance condition; and to perform horizontal adjustment on the measuring device when the difference between the warp monitoring data and the warp reference data meets the horizontal imbalance condition.

2. A monitoring and adjustment method, applied to the measuring equipment monitoring device as described in claim 1, for monitoring and maintaining the measuring equipment, wherein the measuring equipment is used to measure the thickness of a wafer substrate, and a reference wafer is mounted on the measuring equipment, characterized in that... This includes repetitive monitoring and adjustment processes; The monitoring and adjustment process described in a single instance includes: Based on the reference wafer, measurements are performed using the measuring equipment to obtain a set of monitoring data; the set of monitoring data includes thickness monitoring data and warpage monitoring data. The monitoring data set is compared with the reference data set to obtain the differences; the reference data set includes thickness reference data and warpage reference data; the reference data set is used to characterize the thickness and warpage of the reference wafer when the measuring equipment is in standard measurement state; If the difference between the thickness monitoring data and the thickness reference data meets the thickness imbalance condition, the measuring device is aligned and positioned; if the difference between the warpage monitoring data and the warpage reference data meets the horizontal imbalance condition, the measuring device is horizontally adjusted.

3. The monitoring method for measuring equipment according to claim 2, characterized in that, The methods for obtaining the benchmark data include: The measuring device is aligned and positioned and leveled to bring it to the standard measuring state. After the measuring device is in the standard measuring state, the thickness reference data and the warpage reference data are obtained by measuring the thickness reference data and the warpage reference data through the measuring device.

4. The method for monitoring measuring equipment according to any one of claims 2 or 3, characterized in that, The measuring device employs interferometry for measurement and includes: a light output unit, a light detection unit, and a fixing unit; the alignment and positioning adjustment includes: The light output unit is turned on to output a measurement beam. The measurement beam passes through the measurement optical path and is incident on the light detection unit to form a light spot. The light output unit and the measurement optical path are adjusted so that the center of the light spot coincides with the center of the light detection unit, and the area of ​​the light spot is a preset area and the light intensity of the light spot is a preset light intensity. Obtain the standard orientation mark of the reference wafer; based on the standard orientation mark, rotate the reference wafer to perform initial adjustment of the wafer mounting angle; place the initially adjusted reference wafer on the fixed unit and acquire a contour image; based on the contour image, calculate the center offset and angle offset of the reference wafer respectively, and perform fine adjustment of the reference wafer based on the center offset and angle offset.

5. The monitoring method for measuring equipment according to claim 4, characterized in that, The alignment and positioning adjustment, after fine adjustment of the reference wafer, further includes: obtaining the coordinate system direction of the reference wafer and the coordinate system direction of the fixed unit respectively, and confirming that the coordinate system direction of the reference wafer and the coordinate system direction of the fixed unit are consistent, so as to ensure that the coordinate systems of the reference wafer and the fixed unit coincide.

6. The method for monitoring measuring equipment according to any one of claims 4, characterized in that, The measuring device further includes: a contour measuring unit; the fixing unit includes multiple fixing structures; The leveling adjustment includes: adjusting the position of each fixed structure based on a preset position, so as to adjust the levelness of each fixed structure.

7. A thickness measurement method, characterized in that, include, The wafer to be tested is fixed to the measuring device, the measuring device is turned on, and the initial thickness data and warpage data are obtained; Based on the warpage data, the initial thickness data is corrected to obtain the thickness data of the wafer under test; The measuring device is monitored and maintained based on the measuring device monitoring method as described in any one of claims 2 to 6.

8. The thickness measurement method according to claim 7, characterized in that, The step of correcting the initial thickness data based on the warpage data to obtain the thickness data of the wafer under test includes: Based on the warpage data, the oblique cutting angles of each preset measurement point on the wafer under test are obtained; Based on the oblique cutting angle of each measurement point and combined with the initial thickness data, the thickness value of each measurement point is calculated to obtain the thickness data of the wafer to be measured.

9. A terminal, characterized in that, include: A processor and a memory, wherein the memory and the processor are communicatively connected; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to cause the terminal to perform the measurement device monitoring method as described in any one of claims 2 to 6, or the thickness measurement method as described in any one of claims 7 to 8.

10. A computer storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the measurement device monitoring method as described in any one of claims 2 to 6, or the thickness measurement method as described in any one of claims 7 to 8.

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