A method, apparatus, device, and medium for detecting back seal substrate stress

Abstract

The present disclosure provides a method, device, equipment and medium for detecting stress of back sealing substrate; the method comprises: obtaining a first bending moment caused by residual stress in the substrate according to topographic changes before and after back sealing; detecting Young's modulus along the depth direction at any sampling point on the surface of the substrate after back sealing; obtaining a second bending moment of the back sealing layer of the substrate after back sealing at the sampling point according to the Young's modulus along the depth direction at the sampling point; obtaining stress distribution of the back sealing layer along the depth direction at the sampling point based on the first bending moment and the second bending moment according to the property of bending moment balance; and obtaining stress of the transition region between the back sealing layer and the substrate along the depth direction at the sampling point according to the stress distribution of the back sealing layer along the depth direction at the sampling point.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor parameter measurement technology, and in particular to a method, apparatus, device and medium for detecting stress on a back-sealed substrate. Background Technology

[0002] In semiconductor manufacturing processes, to prevent self-doping of single-crystal silicon wafers (also known as substrates or single-crystal substrates) during the epitaxial growth stage, back sealing is typically applied to the silicon wafer. Silicon wafer back sealing technology is a commonly used method to prevent self-doping. It involves depositing a back sealing layer, such as a silicon dioxide film, on the back of the silicon wafer to enclose dopant atoms within the wafer, thereby effectively suppressing the outward diffusion of dopant.

[0003] Residual stress exists in the substrate after back-sealing with a silicon dioxide film. Current methods for detecting this stress typically assume uniform stress in the back-sealing layer and calculate the residual stress generated during the back-sealing process using the Stoney formula based on the change in wafer curvature before and after the back-sealing layer. This residual stress is applied to the entire back-sealing layer. However, in practice, a transition region exists between the back-sealing layer and the substrate. The material properties of this transition region differ from both the back-sealing layer and the substrate, resulting in uneven stress distribution in the back-sealing layer.

[0004] Therefore, the accuracy of current stress detection methods for back seal layers is relatively low. Summary of the Invention

[0005] This disclosure provides a method, apparatus, device, and medium for detecting stress in a back-sealing substrate; it can improve the accuracy of stress detection in the back-sealing layer.

[0006] The technical solution disclosed herein is implemented as follows: In a first aspect, this disclosure provides a method for detecting stress in a back-sealed substrate, the method comprising: The first bending moment caused by residual stress in the substrate is obtained based on the morphological changes before and after back sealing. At any sampling point on the surface of the back-sealed substrate, the Young's modulus along the depth direction at the sampling point is detected. Based on the Young's modulus along the depth direction at the sampling point, the second bending moment of the back seal layer of the back-sealed substrate at the sampling point is obtained; Based on the property of bending moment balance, the stress distribution of the back seal layer along the depth direction at the sampling point is obtained by the first bending moment and the second bending moment; Based on the stress distribution of the back seal layer along the depth direction at the sampling point, the stress along the depth direction in the transition region between the back seal layer and the substrate at the sampling point is obtained.

[0007] Secondly, this disclosure provides an apparatus for detecting stress in a back-sealed substrate, the apparatus comprising: a first acquisition unit, a detection unit, a second acquisition unit, a third acquisition unit, and a fourth acquisition unit; wherein, The first acquisition unit is configured to acquire the first bending moment caused by residual stress in the substrate based on the morphological changes before and after back sealing; The detection unit is configured to detect the Young's modulus along the depth direction at any sampling point on the surface of the back-sealed substrate. The second acquisition unit is configured to acquire the second bending moment of the back seal layer of the back-sealed substrate at the sampling point based on the Young's modulus along the depth direction at the sampling point. The third acquisition unit is configured to acquire the stress distribution of the back seal layer along the depth direction at the sampling point based on the property of bending moment balance, using the first bending moment and the second bending moment. The fourth acquisition unit is configured to acquire, based on the stress distribution of the back seal layer at the sampling point along the depth direction, the stress distribution of the back seal layer along the depth direction at the sampling point.

[0008] Thirdly, this disclosure provides a computing device including a processor and a memory; the processor is configured to execute instructions stored in the memory to implement the method for detecting stress on a back-sealing substrate as described in the first aspect.

[0009] Fourthly, this disclosure provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores at least one instruction, the at least one instruction being executed by a processor to implement the method for detecting stress on a back-sealing substrate as described in the first aspect.

[0010] This disclosure provides a method, apparatus, device, and medium for detecting the stress of a back-sealing substrate. Based on the moment balance properties, the stress of the back-sealing layer is obtained through the bending moments of the substrate and the back-sealing layer. Then, the stress distribution along the depth direction of the back-sealing layer is obtained using the Young's modulus at the sampling point based on the stress of the back-sealing layer. Furthermore, the stress distribution along the depth direction of the transition region is obtained from the stress distribution along the depth direction of the back-sealing layer. This improves the accuracy of stress detection in the back-sealing layer. Attached Figure Description

[0011] Figure 1 This is a schematic cross-sectional view of a substrate with a back seal layer deposited, as provided in this disclosure.

[0012] Figure 2 This is a schematic flowchart of a method for detecting stress in a back-sealing substrate provided in this disclosure.

[0013] Figure 3This is a schematic diagram of the Young's modulus measurement results along the depth direction provided in this disclosure.

[0014] Figure 4 This is a schematic diagram of substrate bending provided in this disclosure.

[0015] Figure 5 This is a schematic diagram showing the radial distribution of the morphology of the silicon wafer before back sealing, as provided in this disclosure.

[0016] Figure 6 This is a schematic diagram showing the radial distribution of the morphology of the back-sealed substrate provided in this disclosure.

[0017] Figure 7 This is a schematic diagram illustrating the morphological differences of the substrate before and after back sealing, as provided in this disclosure.

[0018] Figure 8 This is a schematic diagram of the stress distribution along the depth direction provided in this disclosure.

[0019] Figure 9 This is a schematic diagram of the components of an apparatus for detecting stress on a back-sealing substrate provided in this disclosure.

[0020] Figure 10 This is a schematic diagram of the structure of a computing device provided in this disclosure. Detailed Implementation

[0021] The technical solutions in this disclosure will now be clearly and completely described with reference to the accompanying drawings.

[0022] by Figure 1 Taking the back-sealing substrate shown as an example, in Figure 1 In this design, the back side of the single-crystal substrate faces upwards, and from bottom to top are the single-crystal substrate, the transition region between the single-crystal substrate and the back sealing layer, and the back sealing layer. In this disclosure, the back side of the single-crystal substrate is the surface used for depositing an oxide film, and the surface opposite this is the front side of the single-crystal substrate. Typically, in semiconductor device manufacturing processes, the front side of the single-crystal substrate is used for patterning to form the device. Figure 1 In the transition region, due to the mixture of monocrystalline silicon and silicon oxide, its material differs significantly from that of the monocrystalline substrate and back seal layer. This difference leads to changes in the mechanical properties of the material, such as Young's modulus, compared to the monocrystalline substrate and back seal layer. These changes result in alterations in the residual stress within this region, leading to stress concentration or improper distribution, and consequently, defects such as slip on the back seal layer. Therefore, detecting the stress distribution in the transition region would significantly improve the accuracy of stress detection in the back seal layer.

[0023] Based on this, this disclosure aims to provide a method for detecting the stress of the back-sealing substrate along the depth direction, enabling the detection of the stress distribution in the aforementioned transition region and improving the accuracy of stress detection in the back-sealing layer. See also Figure 2 This disclosure illustrates a method for detecting stress in a back-sealing substrate, the method comprising steps S201 to S205.

[0024] In step S201, the first bending moment caused by residual stress in the substrate is obtained based on the morphological changes before and after back sealing.

[0025] In this disclosure, the substrate undergoes morphological changes due to residual stress in the back-sealing layer before and after back sealing. For single-crystal substrates, since their Young's modulus does not change during back sealing, the first bending moment caused by the residual stress in the single-crystal substrate during morphological changes is only related to the amount of morphological change. Therefore, this disclosure allows calculation of the first bending moment caused by residual stress in the substrate using the morphological changes before and after back sealing.

[0026] It should be noted that since the Young's modulus of the substrate does not change during the back sealing process, the first bending moment is the same for any sampling point on the surface of the substrate with the back sealing layer deposited.

[0027] In step S202, at any sampling point on the surface of the back-sealed substrate, the Young's modulus along the depth direction at the sampling point is detected.

[0028] In this disclosure, combined with Figure 1 The presence of the intermediate transition region means that the stress in the back seal layer is not uniform, but rather unevenly distributed along the depth direction. Therefore, for sampling points on the substrate surface with the deposited back seal layer, the stress distribution along the depth of the back seal layer at each sampling point is also different. In order to obtain the stress distribution along the depth of the back seal layer at all sampling points, multiple sampling points can be set on the substrate surface with the deposited back seal layer, and the technical solution of this disclosure can be applied to each sampling point to obtain the stress distribution along the depth of the back seal layer on the complete substrate surface.

[0029] In some examples, the Young's modulus along the depth direction at the sampling point can be measured using the continuous stiffness method of nanoindentation. For instance, a back-sealed substrate is placed and fixed on the test platform of a nanoindentation instrument. The test platform parameters are adjusted as follows: loading speed: 50 nN / s, continuous stiffness measurement (CSM) vibration frequency: 45 Hz, vibration amplitude: 20 nm, maximum indentation depth: 600 nm, unloading rate: 0.1 mN / s, and holding time: 10 seconds. The Young's modulus along the depth direction at the sampling point is then measured. The measured Young's modulus along the depth direction is shown below. Figure 3 As shown, from Figure 3 As can be seen, the Young's modulus changes significantly in the range of approximately 400 nm to 430 nm in depth. This range can be considered a transition region. Figure 3 The width shown is the width of the transition region.

[0030] In some examples, the substrate after back sealing can be etched to reduce the thickness of the back seal layer before measuring the Young's modulus along the depth direction at the sampling point using a continuous stiffness method based on nanoindentation. Specifically, since the depth of nanoindentation measurement does not exceed 2 to 3 micrometers, such as the aforementioned 600 nanometers, thicker back seal layers (e.g., back seal layers thicker than 600 nanometers) require etching. For example, etching the back seal layer with a 6% concentration of HF can be used to reduce its thickness. Understandably, thinner back seal layers (e.g., back seal layers thinner than 400 nanometers) do not require etching.

[0031] In step S203, the second bending moment of the back seal layer of the back-sealed substrate at the sampling point is obtained based on the Young's modulus along the depth direction at the sampling point.

[0032] In this disclosure, since the stress of the back seal layer is non-uniform along the depth direction, the second bending moment caused by the stress of the back seal layer during the morphological change of the substrate at the sampling point is related to the Young's modulus along the depth direction at the sampling point. Based on the Young's modulus along the depth direction obtained in step S202 above, this disclosure can obtain a means of obtaining the second bending moment.

[0033] In step S204, based on the property of moment balance, the stress distribution of the back seal layer along the depth direction at the sampling point is obtained by the first bending moment and the second bending moment.

[0034] In this disclosure, since the bending moments are balanced, the first bending moment and the second bending moment should be equal. Based on this property of equality, and combining the first and second bending moments, the stress of the back seal layer can be obtained. Furthermore, corresponding to the aforementioned Young's modulus along the depth direction, the stress distribution of the back seal layer along the depth direction can be obtained from the stress of the back seal layer.

[0035] In step S205, the stress distribution along the depth direction of the transition region between the back seal and the substrate at the sampling point is obtained based on the stress distribution of the back seal along the depth direction at the sampling point.

[0036] In this disclosure, the material of the transition region of the back seal layer is different from that of the oxide film. Therefore, in the stress distribution along the depth direction of the back seal layer, there will be stress distribution regions that differ significantly from the stress distribution corresponding to the oxide film material. These stress distribution regions and their corresponding stress distributions can be considered as the stress distribution along the depth direction of the transition region. Specifically, the stress corresponding to the oxide film material can be set as a threshold. When a stress distribution region with a value less than this threshold appears in the stress distribution along the depth direction of the back seal layer at the sampling point, this stress distribution region can be identified as the transition region. Correspondingly, the depth of this stress distribution region is the depth of the transition region, and the stress distribution within this stress distribution region can be represented as the stress distribution of the transition region.

[0037] It should be noted that the above technical solution can be applied to each of all sampling points on the surface of a substrate with a deposited back seal layer. After applying the technical solution of this disclosure to each sampling point, the stress distribution of the back seal layer and transition region along the depth direction at each sampling point can be obtained, and then the stress distribution of the back seal layer and transition region along the depth direction on the entire substrate surface can be obtained.

[0038] Through the above technical solution, this disclosure obtains the stress of the back seal layer based on the bending moments of the substrate and the back seal layer using the bending moment balance properties. Then, based on the stress of the back seal layer, it obtains the stress distribution of the back seal layer along the depth direction using the Young's modulus at the sampling point. Furthermore, it obtains the stress distribution of the transition region along the depth direction from the stress distribution of the back seal layer along the depth direction. This improves the accuracy of stress detection in the back seal layer.

[0039] for Figure 2 In some possible implementations of the technical solution shown, obtaining the first bending moment caused by residual stress in the substrate based on the morphological changes before and after back sealing includes: Provide a substrate before back sealing; The first curvature of the substrate before back sealing is obtained based on the geometry of the substrate before back sealing; The substrate is back-sealed using a thin film deposition process to obtain a back-sealed substrate. The second curvature of the back-sealed substrate is obtained based on the geometry of the back-sealed substrate; The first bending moment caused by residual stress in the substrate is obtained based on the first curvature and the second curvature.

[0040] Specifically, regarding the above implementation method, as follows: Figure 4 The diagram shown illustrates the bending of the substrate, with the front side of the substrate (i.e.) Figure 4 The upper surface of the substrate is subjected to compressive stress and compressive strain, while the back surface of the substrate (i.e., the upper surface) is subjected to compressive stress and compressive strain. Figure 4 The lower surface (of the face) experiences tensile stress and thus tensile strain. The curvature of the front face is... The curvature of the back is , Figure 4 The back side (i.e., the lower surface) shown has a back seal layer deposited, and the radius of the neutral plane is (R1+R2) / 2. For Figure 4 The bending condition shown in the figure, on the plane at a distance Z from the neutral plane in the thickness direction, exhibits the strain as shown in Equation 1: (1) Considering that the substrate is under biaxial stress, the stress at position Z is as shown in Equation 2: (2) in, , This represents the Young's modulus and Poisson's ratio of the substrate at the Z position.

[0041] Based on Equations 1 and 2 above, before depositing the back seal layer, the radial distribution of the substrate morphology before back sealing can be measured using a substrate geometry measurement instrument, as shown below. Figure 5 As shown. In Figure 5 In the diagram, the horizontal axis represents the radial coordinate with the center of the substrate as the zero point, and the vertical axis represents the height (in nm). It should be noted that... Figure 5 The measurement results were obtained after edge removal of the substrate, with an edge removal (EE) amount of 5 mm.

[0042] After depositing the back seal layer on the substrate, the radial distribution of the substrate morphology after back sealing can also be measured using a substrate geometry measurement instrument, such as... Figure 6 As shown, in Figure 6 In the diagram, the horizontal axis represents the radial coordinate with the center of the substrate as the zero point, and the vertical axis represents the height (in nm). By... Figure 6 and Figure 5 Subtract the height values ​​on the corresponding horizontal axis to obtain the height difference, such as... Figure 7 As shown. Based on Figure 7 By performing circle fitting, the curvature change can be obtained as follows: ,in, , These represent the first radius of curvature of the substrate before back sealing and the second radius of curvature of the substrate after back sealing, respectively. It is understandable that... , These are the radii of the neutral plane of the substrate before back sealing and the radii of the neutral plane of the substrate after back sealing, respectively.

[0043] After obtaining the first and second radii of curvature mentioned above, due to the Young's modulus of the single-crystal substrate... Compared with Poisson It will not change, that is to say , Based on this, the first bending moment caused by residual stress in the substrate As shown in Equation 3 below: (3) in, This indicates the diameter of the silicon wafer.

[0044] It should be noted that, for bending moments, the first bending moment and the second bending moment... for Figure 2 In some possible implementations of the technical solution shown, obtaining the second bending moment of the back-sealing layer of the back-sealed substrate at the sampling point based on the Young's modulus along the depth direction at the sampling point includes: The Young's modulus at the sampling point along the depth direction is numerically integrated to obtain the Young's modulus integral value. The second bending moment is obtained based on the integral value of Young's modulus, the radii of curvature of the front and back sides of the back-sealed substrate, and the thickness of the substrate.

[0045] For the example above, specifically, according to the Stoney formula, that is... Typically, the back seal thickness is set to be much smaller than the single-crystal substrate thickness, and the back seal stress is uniformly distributed within the back seal. In this case, the second bending moment of the back seal... As shown in Equation 4 below, and combined with the properties of moment equilibrium, i.e. Equation 4 is: (4) In Equation 4, Indicates the stress of the back seal layer. Indicates the thickness of the single-crystal substrate. This indicates the thickness of the back seal layer.

[0046] In this disclosure, in conjunction with the aforementioned scheme, the back seal layer is not uniformly distributed. Considering the existence of the transition region, based on Equation 4, the stress of the back seal layer should be as shown in Equation 5 below: (5) In Equation 5, This represents the Young's modulus in the back seal layer.

[0047] Furthermore, since the Young's modulus of the transition region differs from that of the back seal layer and the single-crystal substrate, and considering the non-uniformity of stress distribution in the back seal layer, based on the aforementioned Equations 4 and 5, the second bending moment of the back seal layer... As shown in Equation 6 below: (6) for Figure 2 In some possible implementations of the technical solution shown, the step of obtaining the stress distribution of the back seal layer along the depth direction at the sampling point based on the property of bending moment balance, using the first bending moment and the second bending moment, includes: Based on the property of moment balance, the first bending moment is set to be equal to the second bending moment; The stress of the back seal layer is obtained by equating the first bending moment with the second bending moment. Based on the Young's modulus along the depth direction at the sampling point and the stress of the back seal layer, the stress distribution of the back seal layer along the depth direction at the sampling point is obtained.

[0048] For the example above, since the bending moment is balanced, then we have By combining equations 3 and 6 above using this property, we can conclude that: when we know... Given the distribution along the depth direction, we can obtain... Distribution along the depth direction.

[0049] The Young's modulus along the depth direction at the sampling point is measured through the aforementioned step S202. The continuous curve integral shown in Equation 6 can be expressed by the integral of the discrete data as shown in Equation 7 below: (7) in, This indicates a depth interval divided along the depth direction.

[0050] As can be seen from Equation 7, the second bending moment corresponds to the Young's modulus of the back seal layer and is also distributed along the depth. Based on this, the Young's modulus of the sampling points distributed along the depth can be measured, and the stress of the back seal layer can be distributed according to the Young's modulus values ​​corresponding to each depth, thus obtaining the distribution of the back seal layer along the depth direction. During the distribution process, the Young's modulus of the back seal layer can be numerically integrated along the depth to obtain... Next, based on the Young's modulus value corresponding to each depth interval... The ratio of the above numerical integral value determines the stress weight assigned to each depth interval.

[0051] After obtaining the weights corresponding to each depth interval, the stress of the back seal can be distributed along the depth direction to obtain the stress distribution of the back seal along the depth direction.

[0052] like Figure 8 As shown, this diagram illustrates an exemplary stress distribution along the depth direction. It can be seen from the figure that the stress is relatively uniform in the depth range of 0 to 400 nm and approximately 430 nm to 600 nm, while from 400 nm to approximately 430 nm, the stress exhibits a linear decrease in distribution, and the stress distribution from 400 nm to approximately 430 nm is similar to... Figure 3 The transition regions shown are generally consistent in range, that is, the transition region extends from approximately 400 nm to approximately 430 nm, and from... Figure 8 The stress distribution in the region can also be determined.

[0053] Based on the same inventive concept as the aforementioned technical solution, see [link to inventive concept]. Figure 9 This disclosure illustrates a device 90 for detecting stress on a back-sealing substrate, comprising: a first acquisition unit 901, a detection unit 902, a second acquisition unit 903, a third acquisition unit 904, and a fourth acquisition unit 905; wherein, The first acquisition unit 901 is configured to acquire the first bending moment caused by residual stress in the substrate based on the morphological changes before and after back sealing; The detection unit 902 is configured to detect the Young's modulus along the depth direction at any sampling point on the surface of the substrate after back sealing. The second acquisition unit 903 is configured to acquire the second bending moment of the back seal layer of the back-sealed substrate at the sampling point based on the Young's modulus along the depth direction at the sampling point. The third acquisition unit 904 is configured to acquire the stress distribution of the back seal layer along the depth direction at the sampling point based on the properties of bending moment balance, using the first bending moment and the second bending moment. The fourth acquisition unit 905 is configured to acquire, based on the stress distribution of the back seal layer at the sampling point along the depth direction, the stress distribution of the back seal layer along the depth direction at the sampling point.

[0054] In some examples, the first acquisition unit 901 is configured to: Provide a substrate before back sealing; The first curvature of the substrate before back sealing is obtained based on the geometry of the substrate before back sealing; The substrate is back-sealed using a thin film deposition process to obtain a back-sealed substrate. The second curvature of the back-sealed substrate is obtained based on the geometry of the back-sealed substrate; The first bending moment caused by residual stress in the substrate is obtained based on the first curvature and the second curvature.

[0055] In some examples, the detection unit 902 is configured to: For any sampling point on the surface of the back-sealed substrate, the Young's modulus along the depth direction at the sampling point is measured using the continuous stiffness method based on nanoindentation.

[0056] In some examples, the detection unit 902 is also configured to etch the back-sealed substrate to reduce the thickness of the back seal layer before measuring the Young's modulus along the depth direction at the sampling point using the continuous stiffness method based on nanoindentation.

[0057] In some examples, the second acquisition unit 903 is configured to: The Young's modulus at the sampling point along the depth direction is numerically integrated to obtain the Young's modulus integral value. The second bending moment is obtained based on the integral value of Young's modulus, the radii of curvature of the front and back sides of the back-sealed substrate, and the thickness of the substrate.

[0058] In some examples, the third acquisition unit 904 is configured to: Based on the property of moment balance, the first bending moment is set to be equal to the second bending moment; The stress of the back seal layer is obtained by equating the first bending moment with the second bending moment. Based on the Young's modulus along the depth direction at the sampling point and the stress of the back seal layer, the stress distribution of the back seal layer along the depth direction at the sampling point is obtained.

[0059] In some examples, the fourth acquisition unit 905 is configured to: In the stress distribution along the depth direction of the back seal at the sampling point, the depth of the transition region is determined according to the set stress threshold, and the stress distribution along the depth direction of the transition region is obtained.

[0060] Please refer to Figure 10This illustration shows a structural block diagram of a computing device provided in an exemplary embodiment of the present disclosure. In some examples, the computing device 100 can be at least one of devices such as a smartphone, smartwatch, desktop computer, laptop, virtual reality terminal, augmented reality terminal, wireless terminal, and laptop computer. The computing device 100 has communication functions and can access wired or wireless networks. The computing device 100 can refer to one of a plurality of terminals, and those skilled in the art will understand that the number of such terminals can be more or less. In some examples, the computing device 100 can receive data based on the accessed wired or wireless network. It is understood that the computing device 100 undertakes the calculation and processing work of the technical solution of the present disclosure, and the present disclosure does not limit it in this respect.

[0061] like Figure 10 As shown, the computing device in this disclosure may include one or more of the following components: processor 1010 and memory 1020.

[0062] Optionally, the processor 1010 connects various parts within the computing device using various interfaces and lines. It executes various functions and processes data by running or executing instructions, programs, code sets, or instruction sets stored in the memory 1020, and by calling data stored in the memory 1020. Optionally, the processor 1010 can be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor 1010 can integrate one or more of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), Neural-network Processing Unit (NPU), and baseband chip. Specifically, the CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content required for display on the touch screen; the NPU implements Artificial Intelligence (AI) functions; and the baseband chip handles wireless communication. It is understandable that the aforementioned baseband chip may not be integrated into the processor 1010, but may be implemented using a separate chip.

[0063] The memory 1020 may include random access memory (RAM) or read-only memory (ROM). Optionally, the memory 1020 may include a non-transitory computer-readable storage medium. The memory 1020 may be used to store instructions, programs, code, code sets, or instruction sets. The memory 1020 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the various method embodiments described above, etc.; the data storage area may store data created according to the use of the computing device, etc.

[0064] In addition, those skilled in the art will understand that the structure of the computing device shown in the above figures does not constitute a limitation on the computing device. The computing device may include more or fewer components than shown, or combine certain components, or have different component arrangements. For example, the computing device may also include a display screen, camera assembly, microphone, speaker, radio frequency circuit, input unit, sensors (such as accelerometer, angular velocity sensor, light sensor, etc.), audio circuit, WiFi module, power supply, Bluetooth module, etc., which will not be described in detail here.

[0065] This disclosure also provides a computer-readable storage medium storing at least one instruction that is executed by a processor to implement the method for detecting stress on a back-sealing substrate as described in the various embodiments above.

[0066] This disclosure also provides a computer program product including computer instructions stored in a computer-readable storage medium; a processor of a computing device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computing device to perform the method for detecting stress on a back-sealing substrate as described in the various embodiments above.

[0067] Those skilled in the art will recognize that the functions described in this disclosure in one or more of the examples above can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium accessible to a general-purpose or special-purpose computer.

[0068] It should be noted that the technical solutions described in this disclosure can be combined arbitrarily as long as they do not conflict.

[0069] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method of detecting stress in a back sealed substrate, characterized by, The method includes: The first bending moment caused by residual stress in the substrate is obtained based on the radius of curvature before and after back sealing, Young's modulus of the substrate, Poisson's ratio, and silicon wafer diameter. At any sampling point on the surface of the back-sealed substrate, the Young's modulus along the depth direction at the sampling point is detected. Based on the Young's modulus along the depth direction at the sampling point, combined with the radii of curvature of the front and back sides of the back-sealed substrate and the thickness of the substrate, the second bending moment of the back-sealed substrate at the sampling point is obtained. Based on the property of bending moment balance, the stress distribution of the back seal layer along the depth direction at the sampling point is obtained by using the first bending moment and the second bending moment, and according to the weight allocation of Young's modulus. Based on the stress distribution of the back seal layer along the depth direction at the sampling point, the depth of the transition region is determined according to a set stress threshold, so as to obtain the stress along the depth direction of the transition region between the back seal layer and the substrate at the sampling point.

2. The method of claim 1, wherein, The step of obtaining the first bending moment caused by residual stress in the substrate based on the morphological changes before and after back sealing includes: Provide a substrate before back sealing; The first curvature of the substrate before back sealing is obtained based on the geometry of the substrate before back sealing; The substrate is back-sealed using a thin film deposition process to obtain a back-sealed substrate. The second curvature of the back-sealed substrate is obtained based on the geometry of the back-sealed substrate; The first bending moment caused by residual stress in the substrate is obtained based on the first curvature and the second curvature.

3. The method of claim 1, wherein, The step of detecting the Young's modulus along the depth direction at any sampling point on the surface of the back-sealed substrate includes: For any sampling point on the surface of the back-sealed substrate, the Young's modulus along the depth direction at the sampling point is measured using the continuous stiffness method based on nanoindentation.

4. The method of claim 3, wherein, Before measuring the Young's modulus along the depth direction at the sampling point using the continuous stiffness method based on nanoindentation, the method further includes: The substrate after back sealing is etched to reduce the thickness of the back sealing layer.

5. The method according to claim 1, characterized in that, The step of obtaining the second bending moment of the back seal layer of the back-sealed substrate at the sampling point based on the Young's modulus along the depth direction at the sampling point includes: The Young's modulus at the sampling point along the depth direction is numerically integrated to obtain the Young's modulus integral value. The second bending moment is obtained based on the integral value of Young's modulus, the radii of curvature of the front and back sides of the back-sealed substrate, and the thickness of the substrate.

6. The method according to claim 1, characterized in that, The method of obtaining the stress distribution along the depth direction of the back seal layer at the sampling point based on the property of bending moment balance, using the first bending moment and the second bending moment, includes: Based on the property of moment balance, the first bending moment is set to be equal to the second bending moment; The stress of the back seal layer is obtained by equating the first bending moment with the second bending moment. Based on the Young's modulus along the depth direction at the sampling point and the stress of the back seal layer, the stress distribution of the back seal layer along the depth direction at the sampling point is obtained.

7. The method according to claim 1, characterized in that, The step of obtaining the stress along the depth direction of the transition region between the back seal layer and the substrate at the sampling point based on the stress distribution of the back seal layer along the depth direction at the sampling point includes: In the stress distribution along the depth direction of the back seal at the sampling point, the depth of the transition region is determined according to the set stress threshold, and the stress distribution along the depth direction of the transition region is obtained.

8. An apparatus for detecting stress in a back-sealed substrate, characterized in that, The device includes: a first acquisition unit, a detection unit, a second acquisition unit, a third acquisition unit, and a fourth acquisition unit; wherein, The first acquisition unit is configured to acquire the first bending moment caused by residual stress in the substrate based on the radius of curvature before and after back sealing, Young's modulus of the substrate, Poisson's ratio and silicon wafer diameter; The detection unit is configured to detect the Young's modulus along the depth direction at any sampling point on the surface of the back-sealed substrate. The second acquisition unit is configured to acquire the second bending moment of the back sealing layer of the back-sealed substrate at the sampling point based on the Young's modulus along the depth direction at the sampling point, combined with the radii of curvature of the front and back sides of the back-sealed substrate and the thickness of the substrate. The third acquisition unit is configured to acquire the stress distribution of the back seal layer along the depth direction at the sampling point based on the properties of bending moment balance, using the first bending moment and the second bending moment, and according to the weight allocation of Young's modulus. The fourth acquisition unit is configured to determine the depth of the transition region based on the stress distribution of the back seal layer along the depth direction at the sampling point and a set stress threshold, so as to acquire the stress distribution of the transition region between the back seal layer and the substrate along the depth direction at the sampling point.

9. A computing device, characterized in that, The computing device includes a processor and a memory; the processor is configured to execute instructions stored in the memory to implement the method for detecting stress on a back-sealing substrate as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one instruction, which is executed by a processor to implement the method for detecting stress on a back-sealing substrate as described in any one of claims 1 to 7.

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