Wafer detection equipment and wafer detection method

Abstract

The embodiment of the invention provides wafer detection equipment and a wafer detection method. The wafer detection equipment comprises a supporting device used for supporting a wafer; the ultrasonic generator is used for sending ultrasonic waves to the wafer so as to trigger vibration in the wafer, and the propagation direction of the ultrasonic waves is set to form a non-zero included angle with the main surface of the wafer; and the judgment module is used for judging whether the wafer is broken or not.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of semiconductor processing, and in particular, to a wafer detection device and a wafer detection method. BACKGROUND

[0002] In the field of semiconductor and other high-precision manufacturing, wafers, as a key basic material, usually need to maintain high geometric precision and structural integrity in multiple processing links. With the increasing requirements of terminal applications on device performance and process stability, the technical standards of wafers in terms of size tolerance, flatness and surface defect control are also becoming more stringent.

[0003] In the existing manufacturing process, wafers often undergo multiple processes such as cutting, grinding and polishing to optimize and adjust the surface topography and thickness distribution. However, during the above processing, some wafers may be broken, not only causing damage to the product itself, but also having an adverse effect on the corresponding processing equipment. The abnormal cause comes from the internal damage of the silicon wafer in the previous process. The growth of the crystal bar may induce local thermal stress accumulation at the end of the crystal bar solidification, thereby forming micro-cracks, voids or dislocation groups and other crystal structure defects. Deviation of parameters in the cutting process, such as feed rate, wire tension or cooling condition fluctuation, may also bury stress concentration sources or generate potential structural weak areas in the wafer. SUMMARY

[0004] Therefore, the embodiments of the present disclosure provide a wafer detection device and a wafer detection method. The wafer detection device applies ultrasonic waves to the wafer to induce stress response at the internal defects of the wafer, thereby assisting in judging whether the wafer has the required structural stability to withstand subsequent topography adjustment processes, and realizing early screening of wafers with potential cracking risks.

[0005] The technical solution of the present disclosure is implemented as follows: In a first aspect, the embodiments of the present disclosure provide a wafer detection device, comprising: a support device for supporting a wafer; an ultrasonic wave generator for sending ultrasonic waves to the wafer to induce vibration inside the wafer, wherein the propagation direction of the ultrasonic waves is set to form a non-zero angle with the main surface of the wafer; a determination module for determining whether the wafer is broken.

[0006] In some optional examples, the vibration direction of the ultrasonic waves is set to be consistent with the propagation direction of the ultrasonic waves.

[0007] In some optional examples, the propagation direction of the ultrasonic waves forms an incident angle less than 90 degrees with the main surface of the wafer.

[0008] In some optional examples, the mechanical stress induced in the wafer by the ultrasonic wave is not greater than the maximum mechanical stress suffered by the wafer in a chemical mechanical polishing process.

[0009] In some optional examples, the support device is configured to rotate the wafer about a central axis of the wafer.

[0010] In some optional examples, the ultrasonic wave generator is configured to translate in a direction parallel to the main surface of the wafer.

[0011] In some optional examples, the ultrasonic wave generator is configured to output ultrasonic waves having an adjustable frequency.

[0012] In some optional examples, the frequency of the ultrasonic wave is greater than 20000 Hz.

[0013] In some optional examples, the support device is configured to support a plurality of wafers, and the wafer detection device comprises a plurality of ultrasonic wave generators.

[0014] In a second aspect, the embodiments of the present disclosure provide a wafer detection method, which is performed by using the wafer detection device according to the first aspect, and the wafer detection method comprises: supporting a wafer by using a support device; sending an ultrasonic wave to the wafer by using an ultrasonic wave generator to induce vibration inside the wafer, wherein the propagation direction of the ultrasonic wave is configured to form a non-zero angle with the main surface of the wafer; determining whether the wafer is broken by using a determination module.

[0015] The embodiments of the present disclosure provide a wafer detection device and a wafer detection method. The wafer detection device supports a wafer to be detected by using a support device, and applies an ultrasonic wave to the wafer by using an ultrasonic wave generator in a direction forming a non-zero angle with the main surface of the wafer, to induce vibration response of the internal structure of the wafer. If there are defects such as micro-cracks and cavities inside the wafer, the induced vibration may induce local stress concentration in the defect area, and further cause crack propagation or direct breakage. A determination module provided in the wafer detection device is used to detect whether the wafer is broken, and the wafer with high failure risk is screened out accordingly. The detection method takes whether the wafer is broken as the judgment basis, is simple and easy to operate, and is clear in judgment, which helps to remove wafers with hidden dangers in advance before entering the high-stress processing link such as topography adjustment, thereby effectively reducing material waste and equipment damage risk, and significantly improving process stability. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1A schematic diagram of a wafer detection device provided by an embodiment of the present disclosure.

[0017] Figure 2 A schematic diagram of a wafer provided by an embodiment of the present disclosure.

[0018] Figure 3 A schematic diagram of a portion of a wafer detection device provided by an embodiment of the present disclosure.

[0019] Figure 4 A schematic diagram of a portion of a wafer detection device provided by another embodiment of the present disclosure.

[0020] Figure 5 A schematic diagram of a portion of a wafer detection device provided by yet another embodiment of the present disclosure.

[0021] Figure 6 A schematic diagram of a wafer detection device provided by another embodiment of the present disclosure.

[0022] Figure 7 A schematic diagram of a wafer detection device provided by yet another embodiment of the present disclosure.

[0023] Figure 8 A flowchart of a wafer detection method provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0024] In various topography adjustment processes of wafer manufacturing, the wafer needs to go through a series of fine processing steps to obtain higher surface quality and geometric precision. Taking a silicon wafer as an example, in its current mainstream process route, the silicon wafer is usually obtained by cutting a single crystal silicon rod, and then needs to sequentially receive surface treatment operations such as grinding and polishing to further improve its thickness uniformity, surface roughness and flatness. Especially in the integrated circuit manufacturing link, the consistency of the topography of the two surfaces of the silicon wafer is continuously improved, and chemical mechanical polishing (CMP) as one of the key processes has been widely used to realize high-precision regulation of the main surface of the silicon wafer.

[0025] The CMP process relies on the synergistic effect of chemical corrosion and mechanical removal. In the state of applying vertical load and continuous rotation, the silicon wafer is treated by large-area contact with the polishing liquid and the polishing pad. However, the silicon wafer needs to bear a certain degree of normal stress and shear stress in this process. Under normal circumstances, the process parameters are designed and set according to the material properties and geometric dimensions of the silicon wafer, and the stress value generated will not exceed the structural strength of the silicon wafer, so the overall processing process should have good stability.

[0026] However, in actual production, silicon wafer cracking may occur, and once cracked, not only does the product become scrap, but more seriously, it may contaminate or even damage the CMP equipment. For example, if a piece of silicon wafer in the same carrier cracks, the fragments will spread during the rotation of the equipment, scratching the surface of other wafers, contaminating the polishing liquid, and damaging the polishing pad, the platen or the bearing structure and other key components, thereby causing equipment downtime and maintenance, causing production rhythm delay and capacity loss.

[0027] The inventors have carried out a large number of statistical analyses on the above problems, and found that the cracking behavior is not completely random. In a series of experiments on physical analysis and trajectory tracing of the fragments, the inventors noticed that the cracking phenomenon of the wafer often occurs in a specific area, especially the edge of the wafer, the local non-uniform thickness area or the area rich in internal structural defects. These areas are more prone to stress concentration in the topography adjustment process (such as chemical mechanical polishing), becoming the starting source of crack initiation and propagation. Further analysis shows that some wafers have formed micro-cracks, oxygen deposition aggregation or slip bands and other structural defects in the previous process. Such defects are usually difficult to identify by conventional appearance detection or surface imaging means, but under stress, they can quickly evolve into macroscopic rupture, causing process failure and equipment damage. Since the distribution of such internal defects is hidden and invisible, and their structural stability is greatly affected by stress disturbance, conventional detection methods are difficult to screen out such high-risk wafers in time.

[0028] Further research shows that the generation of such fragile wafers is closely related to the growth and cutting process of the upstream crystal bar. For example, at the end of the crystal bar solidification, if the temperature gradient control is unstable, it may induce local thermal stress accumulation, forming micro-cracks, cavities or dislocation groups and other crystal structure defects; in addition, if there is a solid-liquid interface fluctuation in a certain segment of the crystal bar along the axial direction, it may also lead to defect enrichment. On the other hand, parameter deviations in the cutting process, such as feed rate, wire tension or cooling condition fluctuation, may also bury stress concentration sources or create potential structural weak areas in the wafer. However, even if the above defects do not appear early, they may still suddenly break down in subsequent processes due to stress response amplification, constituting an important risk source for wafer reliability.

[0029] Although the existing manufacturing process has set a stress bearing threshold based on the structural mechanical properties of the silicon wafer, and through parameter adjustment of the CMP (chemical mechanical polishing) process, the stress input is controlled within the standard range, but for wafers with hidden internal defects, even if the stress load is within the standard process window, it may still exceed the actual bearing capacity of the local structure, causing sudden cracking failure.

[0030] To identify such potentially high-risk wafers in advance, the inventors initially tried to screen them by manually pressing the wafers, i.e., by manually applying force to the wafers to be tested to observe whether they would break. The practical results show that this method can eliminate some wafers with insufficient structural stability to a certain extent, thereby reducing the risk of breakage in subsequent processing.

[0031] However, this strategy has significant limitations. First, the stress applied by the operator is difficult to unify in size, direction, and action time, and lacks standardization. Second, there are large differences in the methods between different detection personnel, and the repeatability and consistency of the detection results are poor. In addition, manual detection is low in efficiency, high in operation intensity, and heavily dependent on personnel experience and stability, making it difficult to meet the actual needs of high-throughput and refined wafer manufacturing processes.

[0032] To solve the above problems, the wafer detection device and method provided by the embodiments of the present disclosure induce stress response at internal defects of the wafer by applying ultrasonic waves to the wafer, thereby assisting in determining whether the wafer has the structural stability required to withstand subsequent topography adjustment processes, and realizing the early screening of wafers with potential breakage risks.

[0033] Specifically, referring to Figure 1 Some embodiments of the present disclosure provide a wafer detection device 100. The wafer detection device can include a support device 1, an ultrasonic wave generator 2, and a determination module 3. The support device 1 can be used to support the wafer W. The ultrasonic wave generator 2 can be used to send ultrasonic waves to the wafer to induce vibration inside the wafer, wherein the propagation direction of the ultrasonic waves is set to be a non-zero angle with the main surface of the wafer. The determination module 3 can be used to determine whether the wafer W is broken.

[0034] Referring to Figure 2 The wafer W is generally disc-shaped as a whole and has two oppositely arranged main surfaces S. The two main surfaces together constitute the main processing area of the wafer, which usually carries key process steps in the semiconductor device manufacturing process, such as pattern transfer, film deposition, etching, etc. Therefore, various topography adjustment processes involved in the embodiments of the present disclosure mainly revolve around the main surfaces S, including but not limited to surface treatment processes such as grinding, polishing, and chemical mechanical polishing (CMP), aiming to improve the flatness, thickness uniformity, and overall surface quality of the main surfaces.

[0035] The main surfaces S define the thickness direction of the wafer W. The internal structure of the wafer distributed along the thickness direction directly affects the structural stability of the wafer in the subsequent topography adjustment process. Especially in process steps such as CMP that require mechanical force, if there are micro-cracks, cavities, or other structural weak points inside the wafer, the local stress concentration may induce crack propagation, ultimately leading to wafer breakage.

[0036] In a conventional manufacturing process, wafers are usually processed in a horizontal posture. Therefore, in some examples, the wafer W can be arranged substantially horizontally on the support device 1. Referring to Figure 3 , the support device 1 can be provided with a flat support surface to support the wafer W from below, for providing stable support in the vertical direction to withstand the gravity of the wafer itself and limit the vibration or displacement of the wafer under the action of ultrasonic excitation, thereby ensuring the positioning stability of the wafer during detection. To further prevent accidental displacement of the wafer during detection, the support device 1 can also be provided with a vacuum suction mechanism (not shown in the figure) to achieve reliable fixation of the wafer, while meeting the clean process requirements of non-contact or low-stress support.

[0037] In other alternatives, the support device 1 can also adopt an edge clamping structure. For example, the support device 1 can be provided in the form of multiple clamping jaw components (as shown in Figure 4 ) or in the form of a ring (as shown in Figure 5 ) to uniformly clamp or support along the circumferential edge of the wafer W. This structure can avoid large-area contact with the main surface, thereby providing spatial conditions for ultrasonic waves to act on both main surfaces of the wafer W, and is particularly suitable for detection scenarios where both surfaces are excited simultaneously or any one surface is free to radiate.

[0038] The ultrasonic generator 2 can be used to apply ultrasonic waves to the wafer to be detected under non-destructive conditions to excite the internal structure of the wafer W to produce a vibration response. By reasonably setting the propagation path and energy parameters of the ultrasonic waves, a stress field with specific amplitude and spatial distribution characteristics can be formed inside the wafer W. If there are structural defects such as micro-cracks, cavities or dislocation clusters inside the wafer, due to the weaker local structural integrity, they are more likely to form a concentration area in the stress field, thereby inducing crack propagation, deformation or structural damage, providing a physical basis for subsequent structure determination.

[0039] To achieve the above functions, the ultrasonic generator can use various types of transducer devices. In some examples, the ultrasonic generator is a piezoelectric ceramic transducer, which induces mechanical vibration by applying an alternating voltage to the piezoelectric element, and couples the vibration to ultrasonic wave radiation to the surface of the wafer. Such transducers have the advantages of fast response, stable frequency, compact structure, etc., and are suitable for high-integration application scenarios in semiconductor production environments.

[0040] In other examples, the ultrasonic generator can be a magnetostrictive transducer, which drives the magnetostrictive material to produce high-frequency mechanical waves through an alternating magnetic field, and then outputs ultrasonic waves, suitable for detection requirements with lower frequency or higher power.

[0041] The ultrasonic wave can be incident to the surface of the wafer at a non-zero angle. Specifically, in practical applications, in order to enhance the excitation effect and take into account the equipment integration, the propagation direction of the ultrasonic wave can be set to have a certain angle with respect to the main surface of the wafer, rather than being parallel to the main surface of the wafer, so as to excite an asymmetric stress field. As shown in FIG. 7, the incidence direction of the ultrasonic wave and the main surface S of the wafer W form an angle a. The angle a is not zero. Figure 1

[0042] When the ultrasonic wave penetrates the main surface of the wafer, a stress field with a certain spatial distribution and amplitude characteristic is formed inside the wafer. The part of the wafer with low structural strength is easy to become a stress concentration point under ultrasonic excitation, thereby causing local crack propagation, structural deformation, and even inducing wafer rupture.

[0043] The determination module 3 is used to detect the state of the wafer W after receiving the ultrasonic excitation, so as to determine whether the wafer W has cracks or ruptures. Specifically, the determination module 3 can be arranged above the wafer W. After the excitation is completed, the determination module 3 can obtain the surface image of the wafer through image recognition means, and compare the detection image with the initial image to identify whether there are signs of crack propagation or structural damage. Alternatively, the determination module 3 can also collect the acoustic feedback signal of the wafer during the ultrasonic excitation process in real time, and judge whether the wafer has cracks or other structural damage behaviors by analyzing the abnormal change of the echo waveform. According to the actual application requirements, the determination module 3 can also integrate the functions of image recognition and acoustic monitoring to improve the accuracy and robustness of the determination result, so as to effectively achieve the screening goal of high-risk wafers.

[0044] Some embodiments of the present disclosure provide a wafer detection device 100. The wafer detection device 100 supports the wafer W to be detected by the support device 1, and applies ultrasonic waves to the wafer W at a direction having a non-zero angle with respect to the main surface of the wafer W by the ultrasonic generator 2, so as to excite the internal structure of the wafer W to generate a vibration response. If there are defects such as micro-cracks and cavities in the wafer W, the excited vibration may cause local stress concentration in the defect area, and further cause crack propagation or direct rupture. The determination module 3 arranged in the wafer detection device 100 can be used to detect whether the wafer W has ruptures, and screen out wafers with high failure risks according to the detection result. The detection method takes whether the wafer has ruptures as the judgment basis, which is simple to operate and clear to determine, and is helpful to remove wafers with hidden dangers before entering the high-stress processing link such as topography adjustment, so as to effectively reduce the risk of material waste and equipment damage, and significantly improve the process stability.

[0045] ​In some embodiments of the present disclosure, the vibration direction of the ultrasonic wave can be set to be consistent with the propagation direction of the ultrasonic wave, that is, the ultrasonic wave propagates in the form of a longitudinal wave inside the wafer. This longitudinal wave propagation mode can efficiently inject mechanical energy along the propagation path into the wafer, thereby generating dynamic oscillation stress inside the wafer. This mode helps to improve the transmission efficiency of ultrasonic energy inside the wafer and enhances the excitation ability of internal defects such as micro-cracks, cavities, and other internal defects along the propagation direction.

[0046] The use of ultrasonic waves with consistent propagation and vibration directions facilitates the formation of a strong stress response zone in the thickness direction of the wafer W, making the structural weak area (such as internal cracks and delamination) in the thickness direction more susceptible to excitation and structural changes, and even leading to defect expansion or rupture, thereby achieving effective defect screening. This method helps to significantly improve the sensitivity and reliability of defect screening. At the same time, the structural arrangement simplifies the control of the vibration mode by the transducer, thereby simplifying the system structure, making it more suitable for integrated equipment applications, and helping to improve the consistency of detection. In addition, this propagation mode is particularly suitable for detection scenarios that require high energy density or specific coupling paths, providing an efficient and reliable solution for wafer pre-screening in semiconductor manufacturing.

[0047] In some embodiments of the present disclosure, the propagation direction of the ultrasonic wave can form an incident angle of less than 90 degrees with respect to the main surface of the wafer, that is, coupled to the wafer structure in a slanting manner rather than vertically. As shown in FIG. 2, the angle α between the direction of the ultrasonic wave emitted by the ultrasonic wave generator 2 and the surface S of the wafer W is an acute angle. Compared with the vertical incidence mode, the stress field formed inside the wafer by this oblique incidence excitation path has a more complex distribution characteristic, containing not only the vertical stress component along the thickness direction, but also the shear disturbance propagating along the tangential direction of the main surface. Figure 1

[0048] The purpose of this structural design is to improve the excitation ability of potential defects inside the wafer. The inventors have noticed that structural defects such as cracks, cavities, and dislocation clusters in wafers are not always perpendicular to the main surface, and their directions have uncertainty or even significant inclination. In the vertical incidence excitation mode, if the propagation direction is approximately parallel to the direction of a certain type of defect, the ultrasonic wave is difficult to apply effective disturbance to that type of defect during propagation, making it difficult to be fully exposed.

[0049] By introducing an incident angle of less than 90 degrees, the ultrasonic wave can form a slanting stress transmission path in the wafer structure, thereby having a certain excitation effect on defects distributed in different directions. Especially during low-speed rotation of the wafer to improve detection uniformity, the shear disturbance brought by oblique incidence will gradually cover the defect areas in different directions, significantly enhancing the overall defect detection capability.

[0050] ​In some examples, the propagation direction of the ultrasonic wave has an incident angle with respect to the main surface of the wafer in a range between 10 degrees and 90 degrees. By setting the incident angle in this range, it can be helpful to make the detection device more easily contact the wafer surface, and to make the detection device more fine for releasing stress of the wafer.

[0051] In addition, such a composite incident angle setting makes the internal stress of the wafer no longer a single direction of tensile stress or compressive stress, but a composite stress field with spatial gradient characteristics. Such a stress field is closer to the multi-directional load conditions that the wafer bears in actual processes (such as CMP), which helps to simulate the process stress response in advance in the detection stage, so as to realize the accurate screening of high-risk wafers.

[0052] In some embodiments of the present disclosure, in order to ensure that the detection process does not cause additional damage to the wafer itself and maintain the integrity of its subsequent processing, the mechanical stress induced by the ultrasonic wave in the wafer is set to be no more than the maximum mechanical stress that the wafer receives in the chemical mechanical polishing (CMP) process. In the CMP process, the wafer usually bears a down pressure of 20 kPa to 60 kPa (about 3~10 psi), and the internal stress can reach 10 MPa. This stress range has been verified by the inventors to be able to exert the necessary processing pressure on the healthy wafer structure without causing damage to it. Therefore, controlling the ultrasonic excitation intensity in this range can both excite the structural response and reveal potential defects, and avoid additional damage caused by excessive excitation.

[0053] In some embodiments of the present disclosure, the mechanical stress induced in the wafer can be effectively controlled by adjusting the ultrasonic excitation parameters. For this purpose, referring to Figure 1 , the wafer detection device 100 can be provided with a control module 4, which can be configured to limit the transmission intensity of ultrasonic wave energy in the wafer by adjusting the frequency, amplitude and excitation time of the ultrasonic wave, so as to achieve stress control. In addition, the control module 4 can further suppress the occurrence of local stress peaks by optimizing the incident angle and coupling state (such as the material and thickness of the coupling layer) of the ultrasonic wave, and improve the overall excitation uniformity and safety.

[0054] In some embodiments of the present disclosure, referring to Figure 1The wafer detection device 100 can further be provided with a stress monitoring module 5. The stress monitoring module 5 can be integrated in the support device 1 and arranged below the wafer W. The stress monitoring module 5 can be used to monitor the response of the wafer in real time during the excitation process. Specifically, the working principle of the stress monitoring unit is to emit a beam of laser through the wafer W, and determine the stress inside the wafer according to the exit angle of the laser, so as to achieve the detection purpose of different stresses. In this case, the control module 4 can dynamically adjust the excitation parameters based on the monitoring results, so that the intensity of the ultrasonic excitation is always kept within the preset safe range. Through this monitoring-feedback-control closed loop mechanism, precise management of the ultrasonic stress excitation process is realized, so as to ensure the safety of the structure while improving the accuracy of defect identification.

[0055] Therefore, during the entire detection process, the stress field formed inside the wafer is accurately limited within a reasonable range that can excite defects without damaging healthy structures. In particular, considering that the maximum stress that the wafer can withstand in high-stress processes such as CMP is about 10 MPa, the excitation intensity provided by the ultrasonic generator is also set according to this upper limit, ensuring that the detection operation is a non-destructive test. Through the above design, the technical solution of the present disclosure can realize efficient and accurate fragment risk pre-screening without affecting the stability of healthy wafer structures, significantly improving the yield of downstream topography adjustment processes and the stability of equipment operation.

[0056] In some embodiments of the present disclosure, to enhance the directional coverage range of defect excitation, the support device 1 in the wafer detection device 100 can be arranged to drive the wafer W to rotate slowly around its central axis.

[0057] As mentioned earlier, structural defects such as cracks, cavities, and slip bands inside the wafer have significant spatial non-uniformity and directionality. If only static and single-direction ultrasonic excitation is used, it may not be able to fully excite all potential defects, affecting the integrity and reliability of the detection.

[0058] To this end, the present embodiment introduces a wafer rotation mechanism, which continuously rotates the wafer around its central axis at a preset speed during the excitation process, thereby improving the diversity of the excitation wave in the defect direction. In particular, in the case of oblique incidence of ultrasonic waves, the excitation wave will form a composite stress field containing normal and shear components in the wafer. If the wafer remains stationary, it may cause insufficient stress response due to the parallelism of the excitation direction and the extension direction of some defects. Rotating the wafer can make the excitation wave act on the internal structure in different directions in succession, dynamically improving the excitation probability of various directional defects.

[0059] Especially in the scenario of fixed incident angle, the wafer rotation realizes the omnidirectional dynamic coverage of defect orientation, significantly enhances the recognition ability of the system to hidden defects such as asymmetric cracks and inclined slip lines, and improves the detection sensitivity, robustness and repeatability. Therefore, the rotation function not only optimizes the spatial adaptability of defect excitation, but also guarantees the stability of equipment operation in batch detection scenario, and is a key means to realize high reliability of fragment risk screening.

[0060] In some examples, referring to Figure 6 , the support device 1 is fixedly connected to one end of the rotating shaft 10, and the other end of the rotating shaft 10 is connected to a rotating power source 20, such as a motor. The rotating shaft is driven to rotate by the motor, which in turn drives the support device 1 and the wafer supported thereon to rotate around the central axis. Through the above structure, the wafer can realize slow and uniform rotation during ultrasonic excitation, which helps to improve the comprehensiveness of defect excitation and the consistency of detection.

[0061] It should be noted that the embodiments of the present disclosure do not limit the rotation implementation of the support device 1. In addition to the motor driving mode, other mechanical transmission structures or servo control components can also be used to realize the controllable rotation of the wafer according to the specific application requirements. The rotation structure can be adjusted according to the actual equipment layout, and can also be adapted to the beat control and scanning logic of the detection system to ensure the stability and coverage integrity of the detection process.

[0062] In some embodiments of the present disclosure, in order to improve the coverage range of the detection area and enhance the excitation ability of the defect response, the ultrasonic generator 2 can be arranged to be capable of translating in a direction parallel to the main surface of the wafer, as indicated by the arrow in Figure 6 . Figure 6 Specifically, as shown in Figure 6 , the ultrasonic generator 2 can be installed on a slide rail, guide rail or translation driving module 30 with linear motion capability, so that it can translate above the wafer during detection to realize high-density scanning of the surface of the wafer.

[0063] The movement of the ultrasonic generator 2 enables the ultrasonic excitation not only to be limited to single-point excitation at a fixed position, but also to be capable of multi-position excitation along the main surface plane of the wafer, effectively improving the coverage range and detection density. Especially in combination with the rotation of the wafer itself, through the superposition of the translation of the ultrasonic generator 2 and the rotation action, high-density excitation scanning of the entire surface of the wafer can be realized, thereby improving the excitation probability of randomly distributed, asymmetric or small-scale structural defects.

[0064] In addition, the translation driving module 30 can also be used for dynamic adjustment of the excitation position according to the set excitation strategy or stress response feedback signal, to enhance the adaptability and efficiency of detection, and further improve the judgment accuracy and universality of the whole machine. Moreover, in order to match the rhythm of the wafer rotation mechanism, the translation driving module 30 can also be linked with the control module 4 to realize intelligent adjustment of the translation speed, range and acceleration / deceleration process according to the preset strategy, so as to adapt to ultrasonic scanning tasks of different frequencies and different coverage densities. This precise driving structure not only improves the spatial uniformity of ultrasonic excitation, but also enhances the excitation effect of wafer defects, which is helpful to realize high sensitivity and high consistency of defect screening.

[0065] In some embodiments of the present disclosure, the ultrasonic wave generator is configured to be able to output ultrasonic waves with adjustable frequency. The adjustability of the frequency enables the wafer detection device 100 to dynamically optimize the excitation parameters when facing different types of wafer materials, structural defects and size specifications, so as to match the resonance characteristics or defect response characteristics of the wafer to be detected. Specifically, the micro-cracks, cavities or dislocations and other defects that may exist in the wafer will have a significant change in response sensitivity to the ultrasonic wave with the change of the excitation frequency. For example, some sub-micron cracks may be more sensitive to high-frequency excitation, while larger defect areas may be more prone to resonance or stress concentration under low-frequency excitation. By adjusting the frequency of the ultrasonic wave, the stress response of a specific type of defect can be enhanced under non-destructive conditions, thereby improving its detectability.

[0066] In addition, the frequency adjustable capability of the ultrasonic wave can also be used in combination with the stress monitoring module to realize frequency scanning operation, that is, to excite the wafer in sequence in multiple frequency bands to identify the response difference of the wafer at different frequencies. This frequency scanning mechanism helps to further improve the accuracy of defect identification and the universality of the detection system. In combination with the dynamic feedback adjustment function of the control module, the technology can realize optimal detection performance within the safe excitation range, thereby more efficiently completing the early screening work of high-risk wafers.

[0067] In some embodiments of the present disclosure, in order to ensure that the excitation waveform can effectively penetrate the thickness of the wafer and form a stable stress field inside the wafer, the frequency of the ultrasonic wave output by the ultrasonic wave generator 2 is set to be greater than 20,000 Hz. This frequency band belongs to the standard "ultrasonic" frequency range, which can effectively excite the mechanical response in high-hardness materials such as silicon wafers.

[0068] In some examples, the frequency of the ultrasonic wave can be selected in the range of 20 kHz to 5 MHz, and the specific value is set according to the wafer thickness, defect size characteristics and desired excitation mode (such as longitudinal wave or transverse wave). For example, the lower frequency band (20 kHz to 100 kHz) is suitable for exciting large-size cracks or penetration detection, while the higher frequency band (above 500 kHz) is more suitable for revealing micro-cracks, cavities and other local stress concentration points.

[0069] By setting the frequency to be no less than 20000Hz, it can be ensured that the excitation has the ability to penetrate and limit the energy loss of the sound wave in the air, while avoiding artificial interference and detection errors, thereby providing a basic guarantee for subsequent high-sensitivity and non-destructive structure defect identification.

[0070] In addition, in some other embodiments of the present disclosure, the adjustment of the ultrasonic frequency can also be linked with the control module 4, and the frequency setting can be automatically adjusted according to a preset strategy or sensor feedback, thereby forming a closed-loop excitation control system, and further improving the discrimination ability and detection consistency for wafers with high fragment risk.

[0071] In some embodiments of the present disclosure, referring to Figure 7 , the support device 1 of the wafer detection equipment 100 can be configured to support multiple wafers W at the same time, and accordingly, the wafer detection equipment 100 can include multiple ultrasonic generators 2 to realize synchronous or parallel detection of multiple wafers, thereby significantly improving the detection efficiency in batch pre-screening scenarios.

[0072] As shown in Figure 7 , the multiple wafers W are arranged vertically with approximately the same coaxial degree and are spaced apart from each other to leave sufficient space for the transmission of ultrasonic waves. In an example not shown, the support device 1 can also adopt a parallel arrangement of the stage structure, a slot-type bracket structure, or a rotary arrangement of the turntable structure for arranging multiple wafers according to a regular spacing to facilitate sequential or parallel ultrasonic excitation and response monitoring.

[0073] Further, the multiple ultrasonic generators can be arranged above and below the wafers W and correspond to the two main surfaces of each wafer respectively, so as to simultaneously apply ultrasonic excitation from both sides of the wafer to form an incident wave field superimposed from above and below. Such a structural configuration can significantly improve the spatial coverage capability of defect excitation and enhance the overall perception of the wafer structure, thereby improving the integrity and accuracy of defect identification.

[0074] Specifically, by simultaneously applying ultrasonic excitation from above and below, a more complex and uniform stress field distribution can be formed inside the wafer, which is particularly helpful for triggering deep defects in the center region or asymmetric structure of the wafer. For example, the triggering probability of structural weaknesses such as non-vertical cracks, hidden slip bands, and buried cavities is significantly increased. Under the premise of not significantly prolonging the detection time, this double-sided excitation strategy can effectively improve the sensitivity and robustness of detection.

[0075] In some embodiments, the excitation parameters of the plurality of ultrasonic generators, such as frequency, phase, power and incident angle, can be independently adjusted, and can also be jointly controlled by the control system to implement cooperative excitation. By constructing a composite excitation wave field with frequency difference, phase difference or direction difference, the defect excitation spectrum domain can be further expanded, and a non-destructive detection platform with strong adaptability and wide coverage can be constructed.

[0076] Referring to Figure 8 Some embodiments of the present disclosure also provide a wafer detection method, which is executed by using the wafer detection device 100 according to the above, and can include: S01, supporting the wafer by using the supporting device; S02, sending ultrasonic waves to the wafer by the ultrasonic generator to induce vibration in the interior of the wafer, wherein the propagation direction of the ultrasonic waves is set to be a non-zero angle with the main surface of the wafer; S03, determining whether the wafer is broken by the determination module.

[0077] It should be noted that the technical solutions disclosed in the present disclosure can be combined arbitrarily without conflict.

[0078] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A wafer inspection apparatus characterized by comprising: The wafer detection device comprises: a support device for supporting a wafer; an ultrasonic wave generator for transmitting ultrasonic waves to the wafer to induce vibration inside the wafer, wherein a propagation direction of the ultrasonic waves is arranged to form a non-zero angle with a main surface of the wafer; a determination module for determining whether the wafer is cracked.

2. The wafer inspection apparatus of claim 1, wherein The vibration direction of the ultrasonic waves is arranged to be consistent with the propagation direction of the ultrasonic waves.

3. The wafer inspection apparatus of claim 2, wherein The propagation direction of the ultrasonic waves forms an incident angle of less than 90 degrees with respect to the main surface of the wafer.

4. The wafer inspection apparatus of claim 1, wherein The mechanical stress induced by the ultrasonic waves in the wafer is not greater than the maximum mechanical stress suffered by the wafer in a chemical mechanical polishing process.

5. The wafer inspection apparatus according to any one of claims 1 to 4, wherein The support device is arranged to be able to rotate the wafer around a central axis of the wafer.

6. The wafer inspection apparatus of claim 5, wherein The ultrasonic wave generator is arranged to be able to translate in a direction parallel to the main surface of the wafer.

7. The wafer inspection apparatus according to any one of claims 1 to 4, wherein The ultrasonic wave generator is configured to be able to output ultrasonic waves with an adjustable frequency.

8. The wafer inspection apparatus of claim 7, wherein The frequency of the ultrasonic waves is greater than 20000 Hz.

9. The wafer inspection apparatus according to any one of claims 1 to 4, wherein The support device is arranged to be able to support a plurality of wafers, and the wafer detection device comprises a plurality of ultrasonic wave generators.

10. A wafer inspection method, characterized by, The wafer detection method is performed by using the wafer detection device according to any one of claims 1 to 9, the wafer detection method comprising: supporting a wafer by a support device; transmitting ultrasonic waves to the wafer by an ultrasonic wave generator to induce vibration inside the wafer, wherein a propagation direction of the ultrasonic waves is arranged to form a non-zero angle with a main surface of the wafer; determining whether the wafer is cracked by a determination module.

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