A wafer defect analysis and detection method based on Fresnel polarization reflection formula

Abstract

This invention provides a wafer defect analysis and detection method based on the Fresnel polarization reflection formula, belonging to the field of defect detection technology. This invention uses a calibrated polarization detector to perform multi-angle inversion of defect feature intensity on both a known defective wafer and a wafer to be inspected. Based on the multi-angle inversion results of the defect feature intensity of the known defective wafer, defect judgment rules are generated to identify whether defects exist on the surface of the wafer to be inspected. This invention requires no hardware modification or multi-angle physical detection; it accurately calculates the defect feature intensity at any incident angle within a fixed single-angle polarization reflection signal, combined with the physical laws of the Fresnel polarization reflection formula. This fully leverages the precise characterization advantages of polarization imaging, improves the accuracy and versatility of multi-angle defect feature intensity inversion, reduces detection costs, and simplifies the detection process.

Description

Technical Field

[0001] This invention belongs to the field of defect detection technology, and in particular relates to a wafer defect analysis and detection method based on the Fresnel polarization reflection formula. Background Technology

[0002] In the field of dark-field defect detection for precision devices such as wafers, the current mainstream domestic technology is the fixed single-angle incident dark-field detection method. This typically uses a fixed 45° incident angle for dark-field imaging detection, with some solutions incorporating polarization imaging to enhance the contrast between defects and the background. This technology captures dark-field images of the wafer surface and extracts the difference in reflection signals between defects and a perfect background to identify and detect defects such as scratches, particles, steps, and residual adhesive. However, to achieve multi-angle detection, the industry requires hardware adjustments to the incident angle of the light source, enabling multiple shots and images from different angles.

[0003] Existing dark-field imaging detection uses a fixed single angle, which can only present the contrast between defects and the background at that angle. Some defects have small differences in reflected signals and low contrast at this angle, resulting in the inability to identify minute defects or certain types of defects, leading to serious missed detection problems. If multi-angle incident detection is achieved through hardware adjustments, it is necessary to modify hardware equipment such as the light source and stage, increasing equipment procurement and maintenance costs. At the same time, multiple shots and imaging will prolong the detection process, reduce detection efficiency, and the high precision requirements of hardware angle adjustment make it difficult to implement in engineering. Moreover, existing polarization detection simply collects polarization signals without combining optical physics laws to quantify the correlation between polarization state, incident angle, and defect feature intensity, failing to fully leverage the advantages of polarization in accurately characterizing defect features. Summary of the Invention

[0004] To address the problems of single-angle missed detection, high cost of multi-angle hardware detection, and underutilization of polarization advantages in existing wafer defect dark-field detection technologies, this invention provides a wafer defect analysis and detection method based on the Fresnel polarization reflection formula, comprising the following steps:

[0005] The polarization detector is calibrated to obtain the calibrated polarization detector and its response coefficient.

[0006] Based on the calibrated polarization detector and response coefficient, multi-angle inversion of defect feature intensity is performed on the known defect wafer and the wafer to be tested, respectively, to obtain the multi-angle inversion results of defect feature intensity of the known defect wafer and the wafer to be tested; defect judgment rules are generated based on the multi-angle inversion results of defect feature intensity of the known defect wafer.

[0007] Based on the multi-angle inversion results of the defect characteristic intensity of the wafer under test and the defect judgment rules, defects on the surface of the wafer under test are identified.

[0008] Furthermore, the response coefficients include the response coefficient of the calibrated polarization detector to the intensity of the s-polarized reflected signal and the response coefficient of the calibrated polarization detector to the intensity of the p-polarized reflected signal.

[0009] Furthermore, the specific method for performing multi-angle inversion of defect feature intensity on the known defect wafer and the wafer to be inspected based on the calibrated polarization detector and response coefficient is as follows:

[0010] Set the range of incident angles, including several target incident angles;

[0011] Based on the calibrated polarization detector and response coefficient, the defect feature intensity of the known defect wafer and the wafer to be tested is obtained at all target incident angles within the incident angle range.

[0012] Based on the defect feature intensities of the known defective wafer and the wafer to be tested at all target incident angles within the incident angle range, multi-angle inversion results of the defect feature intensities of the known defective wafer and the wafer to be tested are generated respectively.

[0013] Furthermore, the specific method for obtaining the defect feature intensity of the known defect wafer and the wafer to be tested at all target incident angles within the incident angle range is as follows:

[0014] Select a fixed incident angle from all target incident angles, and use a calibrated polarization detector to collect the s-polarization reflection signal intensity and p-polarization reflection signal intensity of the known defect wafer and the wafer to be tested at the fixed incident angle;

[0015] An angle-polarization-background reflectivity library is established within the incident angle range; the s-polarization background reflectivity and p-polarization background reflectivity corresponding to a fixed incident angle are obtained from the angle-polarization-background reflectivity library, and the intrinsic defect characteristics of a known defect wafer and a wafer to be tested are calculated at a fixed incident angle in combination with the response coefficient; the intrinsic defect characteristics include s-polarization defect intrinsic characteristics and p-polarization defect intrinsic characteristics.

[0016] Given the defective wafer and the wafer to be inspected, the intrinsic characteristics of s-polarization defects and p-polarization defects of any wafer are shown in the following formulas:

[0017] ;

[0018] ;

[0019] in, For the intrinsic characteristics of s-polarization defects in any wafer, For the intrinsic characteristics of p-polarization defects on any wafer, Let be the intensity of the s-polarized reflected signal of any wafer at a fixed incident angle. Let p be the intensity of the p-polarized reflected signal of any wafer at a fixed incident angle. For a fixed incident angle, the s-polarized background reflectivity is... For a fixed incident angle, the p-polarized background reflectivity The response coefficient of the calibrated polarization detector to the intensity of the s-polarized reflected signal is given. The response coefficient of the calibrated polarization detector to the intensity of the p-polarized reflected signal is given. To fix the incident angle;

[0020] Based on the intrinsic defect characteristics of the known defective wafer and the wafer to be tested at a fixed incident angle, the defect characteristic intensity of the known defective wafer and the wafer to be tested at all target incident angles is calculated.

[0021] Furthermore, the specific method for establishing an angle-polarization-background reflectivity library within the incident angle range is as follows:

[0022] Based on the Fresnel polarization reflection coefficient formula, calculate the s-polarization reflection coefficient and p-polarization reflection coefficient corresponding to each target incident angle;

[0023] Based on the s-polarization reflection coefficient and p-polarization reflection coefficient corresponding to each target incident angle, calculate the s-polarization background reflectivity and p-polarization background reflectivity corresponding to each target incident angle.

[0024] An angle-polarization-background reflectivity library is established based on the s-polarization background reflectivity and p-polarization background reflectivity corresponding to the incident angles of all targets.

[0025] Furthermore, the specific method for calculating the defect feature intensity of the known defect wafer and the wafer to be inspected at all target incident angles is as follows:

[0026] Based on the intrinsic defect characteristics of the known defective wafer and the wafer to be tested at a fixed incident angle, and the s-polarized background reflectivity and p-polarized background reflectivity corresponding to all target incident angles, the defect characteristic intensity of the known defective wafer and the wafer to be tested at all target incident angles is calculated.

[0027] Furthermore, the multi-angle inversion results of the defect feature intensity include the peak angle of the defect feature intensity, the valley angle of the defect feature intensity, the angle variation law, and the polarization contribution characteristics;

[0028] The peak angle of defect feature intensity is the target incident angle corresponding to the maximum value of defect feature intensity among all target incident angles for a known defect wafer or a wafer to be tested.

[0029] The valley angle of the defect feature intensity is the target incident angle corresponding to the minimum value of the defect feature intensity among all target incident angles for a known defect wafer or a wafer to be tested.

[0030] The angle variation law is the monotonic change amount of the defect feature intensity of the known defect wafer or the wafer to be tested with the target incident angle and the rate of change of the defect feature intensity with the target incident angle.

[0031] The polarization contribution characteristics include the proportion of s-polarized background reflectance and p-polarized background reflectance of a known defective wafer or a wafer under test at each target incident angle.

[0032] Furthermore, defect determination rules are generated based on the multi-angle inversion results of the defect feature intensity of known defective wafers. The specific method is as follows:

[0033] The defect type determination rule is determined based on the peak angle of defect characteristic intensity, valley angle of defect characteristic intensity, angle variation law and polarization contribution characteristics of known defective wafers;

[0034] A defect feature intensity detection threshold is set. When the defect feature intensity of the wafer under test is greater than the defect feature intensity detection threshold at any current target incident angle, it is determined that a defect can be detected at the current target incident angle; otherwise, it is determined that a defect cannot be detected at the current target incident angle.

[0035] If the defect feature intensity corresponding to at least three target incident angles of the wafer under test is greater than the defect feature intensity detection threshold, the wafer under test is determined to have a defect, and the defect type of the wafer under test is determined according to the defect type determination rule; otherwise, the wafer under test is determined to have no defect.

[0036] The beneficial effects of adopting the above technical solution are as follows: The wafer defect analysis and detection method based on the Fresnel polarization reflection formula provided by this invention requires no hardware modification or multi-angle physical detection. It extracts the intrinsic features of defects solely through polarized reflection signals at a fixed incident angle, combined with the physical laws of the Fresnel polarization reflection formula, and accurately calculates the defect feature intensity at any target incident angle within the incident angle range. Simultaneously, it obtains the variation law of defect feature intensity with the target incident angle. This fully leverages the precise characterization advantages of polarization imaging, improves the accuracy and versatility of multi-angle inversion of defect feature intensity, reduces detection costs, and simplifies the detection process. Attached Figure Description

[0037] Figure 1 Flowchart of the wafer defect analysis and detection method based on Fresnel polarization reflection formula provided in Embodiment 1 of the present invention;

[0038] Figure 2The curves showing the variation of defect feature intensity with target incident angle for all target incident angles within the selected incident angle range provided in Embodiment 1 of the present invention. Detailed Implementation

[0039] The specific implementation methods of this application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0040] Example 1:

[0041] A wafer defect analysis and detection method based on Fresnel polarization reflection formula, such as Figure 1 As shown, it includes the following steps:

[0042] Step 1: Calibrate the polarization detector to obtain the calibrated polarization detector and response coefficients;

[0043] Before calibrating the polarization detector, fix it in a stable position on the optical platform. The calibration process only needs to verify the response of the polarization detector itself, without needing a known defective wafer or the wafer to be tested. The light intensity of the standard polarization light source has been precisely calibrated at the factory, i.e., the s-polarized light intensity. and p-polarized light intensity All are known constant values.

[0044] The polarization detector was calibrated using a standard polarization light source, and the response coefficient of the calibrated polarization detector to the intensity of the s-polarized reflected signal was obtained. The response coefficient of the polarization detector to the intensity of the p-polarized reflected signal. The specific method is as follows:

[0045] An S-polarizer is installed in front of a standard polarized light source to ensure that the emitted light is pure S-polarized light; the S-polarized light is aligned with the photosensitive area of ​​the polarization detector, maintaining a stable optical path free from stray light interference; the measured S-polarized light intensity is then acquired using the polarization detector. Based on the calibrated s-polarized light intensity and the measured s-polarized light intensity Calculate the response coefficient of the polarization detector to the intensity of the s-polarized reflected signal. As shown in the formula below:

[0046] ;

[0047] Replace the polarizer of the standard polarizing light source with a p-polarizing polarizer to ensure that the emitted light is pure p-polarized light; keep the optical path position unchanged, and collect the measured p-polarized light intensity using a polarization detector. Based on the calibrated p-polarized light intensity and the measured p-polarized light intensity Calculate the response coefficient of the polarization detector to the intensity of the p-polarized reflected signal. As shown in the formula below:

[0048] ;

[0049] Response coefficient and Determined by the detector hardware parameters and fixed after calibration, this embodiment performs system calibration on the polarization detector to obtain the calibrated polarization detector and its response coefficient. The response coefficient of the calibrated polarization detector to the intensity of the s-polarized reflected signal is... The response coefficient of the calibrated polarization detector to the intensity of the p-polarized reflected signal. By calibrating the response coefficients of the polarization detector to different polarization components, systematic errors in the hardware are eliminated, ensuring the accuracy of subsequent extraction of intrinsic defect features.

[0050] Step 2: Set the incident angle range, including several target incident angles; establish an angle-polarization-background reflectivity library within the incident angle range;

[0051] In this embodiment, the incident angle range is set to 15° to 75°. Several target incident angles are selected within the incident angle range according to the detection accuracy requirements. When selecting the target incident angle, an equal angle interval can be set according to the detection accuracy requirements, and the target incident angle is selected based on the equal angle interval. In this embodiment, the equal angle interval is set to 5°, and the target incident angles selected based on the equal angle interval are 15°, 20°, 25°...75° in sequence.

[0052] Based on the Fresnel polarization reflection coefficient formula, calculate the s-polarization reflection coefficient and p-polarization reflection coefficient corresponding to each target incident angle; target incident angle Corresponding s-polarization reflection coefficient and p-polarized reflection coefficient As shown in the formula below:

[0053] ;

[0054] ;

[0055] in, Let be the refractive index of the incident medium. The refractive index is that of the wafer; in this embodiment, the incident medium is air.

[0056] The Fresnel polarization reflection coefficient formula is an optical formula used to describe the quantitative relationship between the reflection coefficient, the angle of incidence, and the refractive index of the medium when light undergoes polarization reflection at a smooth interface between two isotropic media. It includes two branches: s-polarization and p-polarization. s-polarization, also known as transverse polarization, is polarized light with the electric field direction perpendicular to the plane of incidence, which is the plane formed by the incident ray from the light source and the normal to the wafer surface. p-polarization, also known as longitudinal polarization, is polarized light with the electric field direction parallel to the plane of incidence.

[0057] The polarization reflection coefficient describes the ratio of the amplitude of the reflected light to the amplitude of the incident light when light is reflected at the interface of a medium. It is a dimensionless physical quantity, and the square of its absolute value is the reflectivity.

[0058] This embodiment sets the incident angle range to 15° to 75° to cover the key angles for wafer defect detection, fully characterizing the angular variation law of defect feature intensity. Using the Fresnel polarization reflection formula, the background reflectivity corresponding to s-polarization and p-polarization in the defect-free area of ​​the wafer within the incident angle range of 15° to 75° is accurately calculated, providing reference physical data for subsequent calculation of defect feature intensity. In this embodiment, background reflectivity is the core parameter characterizing the reflection law of a perfect surface under different angles and polarizations.

[0059] Calculate the s-polarized background reflectance and p-polarized background reflectance corresponding to each target incident angle based on the s-polarized and p-polarized reflectance. Corresponding s-polarized background reflectance and p-polarized background reflectivity As shown in the formula below:

[0060] ;

[0061] ;

[0062] An angle-polarization-background reflectivity library is established based on the s-polarization background reflectivity and p-polarization background reflectivity corresponding to all target incident angles, serving as core physical prior data.

[0063] Background reflectivity is the ratio of the intensity of reflected light to the intensity of incident light in a defect-free region of a wafer. It is precisely calculated using the Fresnel polarization reflection formula and serves as a benchmark parameter for calculating defect characteristic intensity. The s-polarized background reflectivity of a defect-free region of a wafer varies with the incident angle. As the incident angle θ increases, the p-polarized background reflectivity first decreases, then approaches 0 near the Brewster angle of silicon (≈73.8°), and increases after exceeding the Brewster angle. This characteristic provides a physical basis for improving the contrast of defect feature intensity inversion. This characteristic can be used to achieve precise suppression of background reflection and improve the contrast of defect feature intensity.

[0064] Step 3: Based on the angle-polarization-background reflectivity library, calculate the intrinsic defect characteristics of the known defect wafer and the wafer to be tested at a fixed incident angle;

[0065] A fixed incident angle is selected from all target incident angles, and the s-polarization reflection signal intensity and p-polarization reflection signal intensity of the known defect wafer and the wafer to be tested are collected at the fixed incident angle using a calibrated polarization detector;

[0066] Obtain a fixed incident angle from the angle-polarization-background reflectivity library. Corresponding s-polarized background reflectance and p-polarized background reflectivity ;

[0067] Calculate a fixed incident angle The intrinsic defect characteristics of known defective wafers and wafers to be tested are described below, including intrinsic characteristics of s-polarization defects and intrinsic characteristics of p-polarization defects;

[0068] Intrinsic characteristics of s-polarization defects in arbitrary wafers and intrinsic characteristics of p-polarized defects As shown in the formula below:

[0069] ;

[0070] ;

[0071] in, Let be the intensity of the s-polarized reflected signal of any wafer. Let be the intensity of the p-polarized reflected signal of any wafer;

[0072] Taking a known defective wafer as an example, this embodiment sets a fixed incident angle as follows: A wafer with known defects was fixed on a polarization detection experimental platform. The incident angle of the light source was set to a fixed incident angle of 45°. A calibrated polarization detector was used as the signal acquisition end to collect the s-polarization reflection signal intensity of the wafer with known defects at a fixed incident angle of 45°. and p-polarized reflected signal intensity Obtain a fixed incident angle from the angle-polarization-background reflectivity library. Corresponding s-polarized background reflectance and p-polarized background reflectivity ; Calculate the fixed incident angle The intrinsic defect characteristics of a known defective wafer, including the intrinsic characteristics of s-polarization defects and p-polarization defects, are shown in the following formula:

[0073] ;

[0074] ;

[0075] in, The intrinsic characteristics of s-polarization defects in a known defective wafer are given. The intrinsic characteristics of p-polarized defects in a known defect wafer are the inherent physical properties of the defect itself, determined only by the defect's roughness, refractive index, and geometric structure, and are independent of the incident angle of the light source. They are the core key parameters for realizing multi-angle inversion of defect characteristic intensity.

[0076] Step 4: Based on the intrinsic defect characteristics of the known defective wafer and the wafer to be inspected at a fixed incident angle, calculate the defect characteristic intensity of the known defective wafer and the wafer to be inspected at all target incident angles;

[0077] This step is the core step of this embodiment. Combining the angle-polarization-background reflectivity library from step 1 and the defect intrinsic features extracted in step 3, the incident angle of any target within the incident angle range is directly calculated and inverted using the calculation formula derived from the Fresnel polarization reflection law. The defect feature intensity can be measured without any hardware multi-angle detection, achieving the goal of moving from single-angle acquisition to full-angle calculation.

[0078] Based on the intrinsic defect characteristics of the known defective wafer and the wafer to be tested at a fixed incident angle, and the s-polarized background reflectivity and p-polarized background reflectivity corresponding to all target incident angles, the defect characteristic intensity of the known defective wafer and the wafer to be tested at all target incident angles is calculated, as shown in the following formula:

[0079] ;

[0080] in, At the target incident angle, the wafer with known defects and the wafer to be inspected are... The intensity of the defect characteristics below;

[0081] Taking a known defective wafer as an example, this embodiment obtains the target incident angle from the angle-polarization-background reflectivity library established in step 1. Corresponding s-polarized background reflectance and p-polarized background reflectivity Based on the intrinsic defect characteristics of known defective wafers and the target incident angle Corresponding s-polarized background reflectance and p-polarized background reflectivity Calculate the incident angle of the target on a wafer with known defects. Defect characteristic strength below As shown in the formula below:

[0082] ;

[0083] Defect feature strength is the core quantitative indicator for defect detection. The numerical value characterizes the degree of difference in polarization background reflectivity between the defective wafer and the perfect wafer at the incident angle of the target, and the defect feature intensity. The larger the value, the more obvious the defect characteristics;

[0084] Calculate the defect feature intensity of the known defect wafer and the wafer to be tested at all target incident angles within the incident angle range, and construct full-angle defect feature intensity datasets for the known defect wafer and the wafer to be tested, respectively.

[0085] Step 5: Based on the defect feature intensity of the known defect wafer and the wafer to be tested at all target incident angles within the incident angle range, generate multi-angle inversion results of the defect feature intensity of the known defect wafer and the wafer to be tested, respectively.

[0086] This step analyzes the full-angle defect feature intensity datasets of the known defect wafer and the wafer to be tested obtained from the inversion, extracts the angular variation law of the defect feature intensity, and organizes and outputs the full-angle intensity data and law analysis results, providing a comprehensive quantitative basis for defect detection and defect attribute analysis.

[0087] Data analysis was performed on the full-angle defect feature intensity datasets of known defect wafers and wafers to be inspected to obtain multi-angle inversion results of defect feature intensity of known defect wafers and wafers to be inspected, including peak angle of defect feature intensity, valley angle of defect feature intensity, angle variation law and polarization contribution characteristics;

[0088] The peak angle of defect feature intensity is the target incident angle corresponding to the maximum value of defect feature intensity among all target incident angles for a known defect wafer or a wafer to be tested.

[0089] The valley angle of the defect feature intensity is the target incident angle corresponding to the minimum value of the defect feature intensity among all target incident angles for a known defect wafer or a wafer to be tested.

[0090] The angle variation law is the monotonic variation trend of the defect feature intensity with the target incident angle and the rate of change of the defect feature intensity with the target incident angle for a known defect wafer or a wafer to be inspected.

[0091] The polarization contribution characteristics include the proportions of s-polarized background reflectance and p-polarized background reflectance at each target incident angle.

[0092] The numerical values ​​of defect feature intensity and the curves and charts of angle variation corresponding to the incident angles of each target within the incident angle range are compiled to generate a standardized multi-angle inversion result report of defect feature intensity, including a full-angle defect intensity data table and a defect intensity angle variation analysis report, thus completing the entire multi-angle inversion process of defect feature intensity.

[0093] Step 6: Generate defect judgment rules based on the multi-angle inversion results of the defect feature intensity of the known defective wafer. Based on the multi-angle inversion results of the defect feature intensity of the wafer to be inspected and the defect judgment rules, identify whether there are defects on the surface of the wafer to be inspected.

[0094] This embodiment sets a defect feature intensity detection threshold as the judgment criterion to avoid misjudging background noise as a defect; defect feature intensity detection threshold As shown in the formula below:

[0095] ;

[0096] in, As the threshold baseline, The baseline noise is used; in this embodiment, the background reflection intensity of the defect-free region of a known defective wafer is used as the threshold baseline. Baseline noise The defect feature intensity detection threshold was calculated. ;

[0097] The judgment rule is set as follows:

[0098] When the defect characteristic strength At that time, determine the target's incident angle. The following methods can detect defects;

[0099] When the defect characteristic strength At that time, determine the target's incident angle. The defect could not be detected.

[0100] Defect feature intensity corresponding to at least three target incident angles of the wafer under inspection If the test result is positive, the wafer to be tested is determined to have a defect; otherwise, the wafer to be tested is determined to have no defect.

[0101] In this embodiment, a 6-inch silicon wafer with a linear scratch of 0.8 μm width located in the center region of the wafer surface is used as the wafer to be inspected. The incident angle range is set to 15° to 75°, with 5° angles as equal intervals. The target incident angles are selected as 15°, 20°, 25°...75°. The defect feature intensity of the wafer under the selected target incident angles is shown in Table 1.

[0102] Table 1. Defect feature intensity data table at the target incident angle;

[0103]

[0104] As shown in Table 1, the defect feature intensity of the wafer under test at all target incident angles is much greater than the defect detection intensity threshold of 0.0049. Therefore, the 13 target incident angles selected in this embodiment can effectively detect the defects of the wafer under test.

[0105] This embodiment generates defect determination rules based on the multi-angle inversion results of the defect feature intensity of a known defective wafer, as shown in Table 2. These rules include different defect types and the peak angle, valley angle, angle variation law, and polarization contribution characteristics of the defect feature intensity for each defect type.

[0106] Table 2 Defect Judgment Rules;

[0107]

[0108] Based on the multi-angle inversion results of the defect feature intensity of the wafer under inspection and the defect judgment rules, defects on the surface of the wafer under inspection are identified, including:

[0109] The defect feature intensity of the wafer under inspection at the selected target incident angle varies with the target incident angle as follows: Figure 2 As shown, within the incident angle range of 15° to 75° in this embodiment, the defect feature intensity of the wafer under test increases monotonically with the increase of the target incident angle, without peak drop or fluctuation, and the overall change rate is 48.8%, that is, the defect feature intensity corresponding to the target incident angle of 75° is 48.8% higher than the defect feature intensity corresponding to the target incident angle of 15°.

[0110] The defect feature intensity is greatest when the target incident angle is 75°, which is the peak value of the defect feature intensity; the defect feature intensity is smallest when the target incident angle is 15°, which is the valley value of the defect feature intensity.

[0111] In this embodiment, within the incident angle range of 15° to 75°, the polarization contribution characteristic of the wafer under test is that the contribution of s-polarized background reflectivity to the defect feature intensity continuously increases with the increase of the target incident angle. When the target incident angle is 75°, the contribution of s-polarized background reflectivity reaches 82.1%, while the contribution of p-polarized background reflectivity is only 17.9%.

[0112] By comparing the defect feature intensity variation pattern, peak value, estimated defect feature intensity, and continuously increasing s-polarization contribution of the wafer under test in this embodiment with the standard defect library, it can be found that the similarity between the defect of the test object and the standard pattern of linear scratch is 98% (≥80% judgment match); therefore, the defect of the wafer under test is determined to be a linear scratch defect, which is completely consistent with the actual physical defect type of the wafer under test.

[0113] Example 2:

[0114] This embodiment proposes an electronic device, including: one or more processors, and a memory, wherein the memory is used to store instructions, and when the instructions are executed by the one or more processors, the one or more processors execute the wafer defect analysis and detection method based on the Fresnel polarization reflection formula.

[0115] The electronic device may be a mobile phone, computer, or tablet computer, etc., and includes a memory and a processor. The memory stores a computer program, which, when executed by the processor, implements the wafer defect analysis and detection method based on the Fresnel polarization reflection formula as described in the embodiments. It is understood that the electronic device may also include input / output (I / O) interfaces and communication components.

[0116] The processor is used to execute all or part of the steps in the wafer defect analysis and detection method based on the Fresnel polarization reflection formula as described in the above embodiments. The memory is used to store various types of data, which may include, for example, instructions for any application or method in the electronic device, as well as application-related data.

[0117] The processor can be implemented as an Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), controller, microcontroller, microprocessor, or other electronic components, and is used to execute the wafer defect analysis and detection method based on the Fresnel polarization reflection formula described in the above embodiments.

[0118] Example 3:

[0119] This embodiment proposes a computer-readable storage medium that stores executable instructions. When these instructions are executed, if they are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0120] The computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the wafer defect analysis and detection method based on the Fresnel polarization reflection formula described in the various embodiments of this application.

[0121] The aforementioned storage media include: flash memory, hard disks, multimedia cards, card-type memory (e.g., SD (Secure Digital Memory Card) or DX (Memory Data Register, MDR) memory), random access memory (RAM), static random-access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic storage, disks, optical discs, servers, APP (Application) application stores, and other media capable of storing program verification codes. These media store computer programs, which, when executed by a processor, can implement the various steps of the wafer defect analysis and detection method based on the Fresnel polarization reflection formula described above.

[0122] Example 4:

[0123] This embodiment proposes a computer program product, including a computer program or instructions, which, when executed by a processor, implements the wafer defect analysis and detection method based on the Fresnel polarization reflection formula.

[0124] Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a computer program product.

[0125] The various embodiments in this application are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0126] The scope of protection of this application is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from the scope and spirit of this disclosure. If such modifications and variations fall within the scope of this disclosure and its equivalents, then the intent of this disclosure also includes these modifications and variations.

Claims

1. A wafer defect analysis and detection method based on Fresnel polarization reflection formula, characterized in that, Includes the following steps: The polarization detector is calibrated to obtain the calibrated polarization detector and its response coefficient. Based on the calibrated polarization detector and response coefficient, multi-angle inversion of defect feature intensity is performed on the known defect wafer and the wafer to be tested, respectively, to obtain the multi-angle inversion results of defect feature intensity of the known defect wafer and the wafer to be tested; defect judgment rules are generated based on the multi-angle inversion results of defect feature intensity of the known defect wafer. Based on the multi-angle inversion results of the defect feature intensity of the wafer under test and the defect judgment rules, the defects on the surface of the wafer under test are identified. The specific method for performing multi-angle inversion of defect feature intensity on known defect wafers and wafers to be inspected based on calibrated polarization detectors and response coefficients is as follows: Set the range of incident angles, including several target incident angles; Based on the calibrated polarization detector and response coefficient, the defect feature intensity of the known defect wafer and the wafer to be tested is obtained at all target incident angles within the incident angle range. Based on the defect feature intensities of the known defective wafer and the wafer to be tested at all target incident angles within the incident angle range, multi-angle inversion results of the defect feature intensities of the known defective wafer and the wafer to be tested are generated respectively. The specific method for obtaining the defect feature intensity of the known defect wafer and the wafer to be tested at all target incident angles within the incident angle range is as follows: Select a fixed incident angle from all target incident angles, and use a calibrated polarization detector to collect the s-polarization reflection signal intensity and p-polarization reflection signal intensity of the known defect wafer and the wafer to be tested at the fixed incident angle; An angle-polarization-background reflectivity library is established within the incident angle range; the s-polarization background reflectivity and p-polarization background reflectivity corresponding to a fixed incident angle are obtained from the angle-polarization-background reflectivity library, and the intrinsic defect features of the known defect wafer and the wafer to be tested under a fixed incident angle are calculated in combination with the response coefficient. The intrinsic defect features include s-polarization defect features and p-polarization defect features. Based on the intrinsic defect characteristics of the known defective wafer and the wafer to be tested at a fixed incident angle, the defect characteristic intensity of the known defective wafer and the wafer to be tested at all target incident angles is calculated.

2. The wafer defect analysis and detection method based on Fresnel polarization reflection formula according to claim 1, characterized in that, The response coefficients include the response coefficients of the calibrated polarization detector to the intensity of the s-polarized reflected signal and the response coefficients of the calibrated polarization detector to the intensity of the p-polarized reflected signal.

3. The wafer defect analysis and detection method based on Fresnel polarization reflection formula according to claim 1, characterized in that, Given the defective wafer and the wafer to be inspected, the intrinsic characteristics of s-polarization defects and p-polarization defects of any wafer are shown in the following formulas: ； ； in, For the intrinsic characteristics of s-polarization defects in any wafer, For the intrinsic characteristics of p-polarization defects on any wafer, Let be the intensity of the s-polarized reflected signal of any wafer at a fixed incident angle. Let p be the intensity of the p-polarized reflected signal of any wafer at a fixed incident angle. For a fixed incident angle, the s-polarized background reflectivity is... For a fixed incident angle, the p-polarized background reflectivity The response coefficient of the calibrated polarization detector to the intensity of the s-polarized reflected signal is given. The response coefficient of the calibrated polarization detector to the intensity of the p-polarized reflected signal is given. To fix the incident angle.

4. The wafer defect analysis and detection method based on the Fresnel polarization reflection formula according to claim 3, characterized in that, The specific method for establishing an angle-polarization-background reflectivity library within the incident angle range is as follows: Based on the Fresnel polarization reflection coefficient formula, calculate the s-polarization reflection coefficient and p-polarization reflection coefficient corresponding to each target incident angle; Based on the s-polarization reflection coefficient and p-polarization reflection coefficient corresponding to each target incident angle, calculate the s-polarization background reflectivity and p-polarization background reflectivity corresponding to each target incident angle. An angle-polarization-background reflectivity library is established based on the s-polarization background reflectivity and p-polarization background reflectivity corresponding to the incident angles of all targets.

5. The wafer defect analysis and detection method based on the Fresnel polarization reflection formula according to claim 4, characterized in that, The specific method for calculating the defect feature intensity of a known defective wafer and a wafer to be inspected at all target incident angles is as follows: Based on the intrinsic defect characteristics of the known defective wafer and the wafer to be tested at a fixed incident angle, and the s-polarized background reflectivity and p-polarized background reflectivity corresponding to all target incident angles, the defect characteristic intensity of the known defective wafer and the wafer to be tested at all target incident angles is calculated.

6. The wafer defect analysis and detection method based on the Fresnel polarization reflection formula according to claim 5, characterized in that, The multi-angle inversion results of the defect feature intensity include the peak angle of the defect feature intensity, the valley angle of the defect feature intensity, the angle variation law, and the polarization contribution characteristics. The peak angle of defect feature intensity is the target incident angle corresponding to the maximum value of defect feature intensity among all target incident angles for a known defect wafer or a wafer to be tested. The valley angle of the defect feature intensity is the target incident angle corresponding to the minimum value of the defect feature intensity among all target incident angles for a known defect wafer or a wafer to be tested. The angle variation law is the monotonic change amount of the defect feature intensity of the known defect wafer or the wafer to be tested with the target incident angle and the rate of change of the defect feature intensity with the target incident angle. The polarization contribution characteristics include the proportion of s-polarized background reflectance and p-polarized background reflectance of a known defective wafer or a wafer under test at each target incident angle.

7. The wafer defect analysis and detection method based on Fresnel polarization reflection formula according to claim 6, characterized in that, Defect judgment rules are generated based on the multi-angle inversion results of defect feature intensity of known defective wafers. The specific method is as follows: The defect type determination rule is determined based on the peak angle of defect characteristic intensity, valley angle of defect characteristic intensity, angle variation law and polarization contribution characteristics of known defective wafers; A defect feature intensity detection threshold is set. When the defect feature intensity of the wafer under test is greater than the defect feature intensity detection threshold at any current target incident angle, it is determined that a defect can be detected at the current target incident angle; otherwise, it is determined that a defect cannot be detected at the current target incident angle. If the defect feature intensity corresponding to at least three target incident angles of the wafer under test is greater than the defect feature intensity detection threshold, the wafer under test is determined to have a defect, and the defect type of the wafer under test is determined according to the defect type determination rule; otherwise, the wafer under test is determined to have no defect.

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