Detection system, detection method and defect detection equipment

Abstract

The invention relates to the technical field of semiconductor front channel detection, discloses a dark field detection system and method, and particularly relates to a detection system, a detection method and defect detection equipment. According to the technical scheme provided by the embodiment of the invention, the oblique incident light beams and the vertical incident light beams with different incident angles are formed by controlling the loading or separating of the adjusting lens group on the propagation path of the incident light beams, so that the adjustment of different incident modes of the incident light beams is realized; and the oblique incident light beam and the vertical incident light beam share one main incident light beam, so that the redundancy of the system is reduced. Moreover, a focusing objective lens which can be synchronously controlled with the adjusting lens group is arranged, and the adjustment of the corresponding focal lengths of the oblique incident beam and the vertical incident beam is realized by controlling the position change of the focusing objective lens on the optical axis of the incident beam, so that the optical path of the oblique incident beam and the optical path of the vertical incident beam are kept consistent.

Description

Technical Field

[0001] The present application relates to the field of semiconductor front-end detection technology, and is a dark field detection system and method, specifically a detection system, a detection method and defect detection equipment. Background Art

[0002] Wafers serve as the substrate for chips. Surface defects on wafers can cause the resulting chips to fail, reducing chip yield and increasing manufacturing costs. Therefore, a common approach is to perform surface defect inspection on wafers before or during chip production. Wafer surface defect inspection involves detecting the presence and location of defects such as grooves, particles, and scratches on the wafer surface.

[0003] At present, dark field scanning systems are commonly used for wafer surface defect detection. The system usually uses a beam splitter prism at the laser outlet to divide the light beam into two incidence modes: vertical incidence and oblique incidence to obtain the scattering information of the defect, and uses the same means to detect and reflect the scattering information of the defect in different directions. Generally, the vertical incidence system includes a set of beam expanders, shaping lenses, and focusing lenses, and the vertical incidence system also includes a set of beam expanders, shaping lenses, and focusing lenses, which are distributed at different positions in the system. However, the beam expanders, shaping lenses, and focusing lenses usually use the same type of lens or lens group, which increases the size of the equipment and the basic cost. In addition, the two subsystems need to be assembled and debugged separately, resulting in problems such as reduced light energy utilization and a cumbersome and complicated debugging process. Summary of the Invention

[0004] In order to address the technical gaps in the prior art, the embodiments of the present application provide a detection system, a detection method, and a defect detection device, which can share some optical devices to perform real-time adjustment of the incident light beam type while ensuring the accuracy of the detection results, thereby reducing system-level costs and installation and debugging costs.

[0005] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present application are as follows:

[0006] In a first aspect, a detection system is provided, comprising: a main incident light beam, the main incident light beam being incident at an oblique angle to an object to be detected and forming a first incident light spot on the surface of the object to be detected; an adjustment mirror group, comprising at least one reflector, which can be optionally configured on a propagation path of the main incident light beam, for changing the propagation direction of the main incident light beam and causing the main incident light beam to propagate to a vertical mirror group; a vertical mirror group, which is used to change the propagation direction of the main incident light beam and form a normal incident light beam relative to the object to be detected, and form a second incident light spot on the surface of the object to be detected; at least one focusing objective lens is provided on the propagation path of the main incident light beam, and focal length adjustment is achieved by controlling the distance between the focusing objective lens and the object to be detected, wherein the first incident light spot and the second incident light spot have the same size, shape, incident position and the same energy distribution.

[0007] In another practicable manner, a movable focusing objective lens is provided on the propagation path of the main incident light beam, and the movable focusing objective lens can be moved along the optical axis of the main incident light beam.

[0008] In another practicable embodiment, a fixed focusing objective lens and an optionally adjustable focusing objective lens are provided on the propagation path of the main incident light beam; the adjustable focusing objective lens follows the adjustment lens group and is optionally configured in the main incident light beam, and the adjustable focusing objective lens is provided close to the object to be detected relative to the fixed focusing objective lens.

[0009] In another practicable embodiment, the vertical mirror group includes two oppositely arranged reflectors, one reflector is used to receive the incident light beam reflected by the adjustment mirror group and project it to the other reflector, and the other reflector is used to project the incident light beam in a normal incidence manner onto the surface of the object to be detected.

[0010] In another practicable manner, the adjustment mirror assembly includes two oppositely disposed reflective mirrors, one for receiving the main incident light beam and projecting it to the vertical objective lens via the other reflective mirror.

[0011] In another practicable manner, the vertical mirror assembly includes a reflector for receiving the incident light beam reflected by the adjustment mirror assembly and projecting the incident light beam onto the surface of the object to be inspected in a normal incidence manner.

[0012] In another practicable manner, a functional optical lens assembly is further provided on the main incident light beam for adjusting the optical state of the main incident light beam.

[0013] In another practicable manner, the functional optical lens assembly includes a polarizer, and the polarizer is used to change the polarization state of the main incident light beam.

[0014] In another practicable manner, the functional optical lens assembly includes a beam expander and a shaping lens, which are used to adjust the shape of the main incident light beam.

[0015] In another practicable manner, the main incident light beam is generated by a laser light source, and its propagation path is changed via a first reflector and a second reflector, thereby forming an incident relationship with the object to be detected at an oblique angle.

[0016] In a second aspect, a detection method is provided, which is applied to the detection system described in any of the above items, and the method includes: determining the type of the incident light beam according to a scanning period; and controlling the adjustment mirror group to enter or move away from the incident light beam propagation path according to the type of the incident light beam, and forming a corresponding first incident light beam or a second incident light beam; each of the scanning periods is only used to generate one type of incident light beam and control the change in the distance of at least one focusing objective lens relative to the object to be detected according to the type of the incident light beam, thereby changing the focal length of the first incident light beam or the second incident light beam.

[0017] In another practicable manner, controlling the adjustment mirror group to enter or move away from the incident light beam propagation path according to the incident light beam type includes: controlling the adjustment mirror group to adjust the height position relative to the object to be detected according to the incident light beam type.

[0018] In another practicable manner, controlling the distance change of at least one focusing objective relative to the object to be detected according to the type of the incident light beam includes: controlling the distance of a movable focusing objective relative to the object to be detected along the optical axis based on the type of the incident light beam.

[0019] In another practicable embodiment, controlling the distance change of at least one focusing objective lens relative to the object to be detected according to the type of the incident light beam includes: adjusting the height of the adjustable focusing objective lens based on the type of the incident light beam so that the adjustable focusing objective lens is loaded into or out of the incident light beam propagation path.

[0020] According to a third aspect, a defect detection device is provided, comprising: a carrier for placing an object to be detected and moving it along an equidistant spiral; a detection system as described in any one of the above items, for sequentially generating a first incident light spot and a second incident light spot having the same size, shape, incident position and the same energy distribution to the surface of the object to be detected based on a scanning period, and generating corresponding first scattered light beams and second scattered light beams through the object to be detected; a detector assembly, for sequentially receiving the first scattered light beam and the second scattered light beam, and generating corresponding scattered light signals; and a processing center, for processing the scattered light signals to obtain detection results.

[0021] The embodiments of the present invention bring the following beneficial effects:

[0022] In the technical solutions provided by the embodiments of the present application, by controlling the movement of the adjustment lens assembly along the propagation path of the incident light beam, oblique incident light beams and vertical incident light beams with different incident angles are formed, thereby achieving adjustment for different incident modes of the incident light beam. The oblique incident light beam and the vertical incident light beam share a single main light beam, reducing system redundancy. Furthermore, by providing a focusing objective lens that can be synchronously controlled with the adjustment lens assembly, the corresponding focal lengths of the oblique incident light beam and the vertical incident light beam can be adjusted by controlling the position of the focusing objective lens on the optical axis of the incident light beam, thereby maintaining the optical path of the oblique incident light beam and the vertical incident light beam consistent.

[0023] Other features and advantages of the present disclosure will be set forth in the following description, or some features and advantages may be inferred or unambiguously determined from the description, or may be learned by practicing the above-mentioned technology of the present disclosure.

[0024] In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0026] The methods, systems, and / or programs in the accompanying drawings will be further described according to exemplary embodiments. These exemplary embodiments will be described in detail with reference to the drawings. These exemplary embodiments are non-limiting exemplary embodiments, wherein example numerals represent similar structures in the various views of the drawings.

[0027] Figure 1 Schematic diagram of the detection system module;

[0028] Figure 2 A structural diagram of the detection system;

[0029] Figure 3 It is another partial structural diagram of the detection system;

[0030] Figure 4 It is a schematic diagram of the overall structure of the detection system;

[0031] Figure 5 Schematic diagram of the detection method flow chart;

[0032] Figure 6 A schematic diagram of the readable medium structure. DETAILED DESCRIPTION

[0033] In order to better understand the above technical solution, the technical solution of the present application is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0034] In the following detailed description, numerous specific details are set forth by way of example in order to provide a thorough understanding of the relevant teachings. However, it will be apparent to one skilled in the art that the present application can be practiced without these details. In other instances, well-known methods, procedures, systems, compositions, and / or circuits have been described at a relatively high level, without detail, to avoid unnecessarily obscuring aspects of the present application.

[0035] Flowcharts are used in this application to illustrate the execution processes performed by the system according to the embodiments of the present application. It should be clearly understood that the execution processes of the flowcharts may not be executed in sequence. Instead, these execution processes may be executed in reverse order or simultaneously. In addition, at least one additional execution process may be added to the flowchart. One or more execution processes may be deleted from the flowchart.

[0036] An embodiment of the present application provides a dark field detection system, which is applied to dark field detection. A light spot is formed by projecting a laser of a specific wavelength onto the surface of the object to be tested, thereby realizing detection of the object to be tested. The object to be tested is a wafer to be tested. In this embodiment, the "wafer" generally refers to a substrate formed of a semiconductor or non-semiconductor material. Examples include (but are not limited to) single crystal silicon, gallium arsenide, gallium nitride, and indium phosphide. Such substrates can typically be found and / or processed in semiconductor manufacturing facilities. In some cases, a wafer may include only a substrate (i.e., a bare chip). Alternatively, a wafer may include one or more layers of different materials formed on a substrate. One or more layers formed on a wafer may be "patterned" or "unpatterned". For example, a wafer may include multiple bare chips with repeatable pattern features.

[0037] Dark-field laser scattering, an effective detection method, is based on the scattering of light. Specifically, the device illuminates the wafer surface with a high-precision laser beam. When the laser encounters surface defects, it generates scattered light. This scattered light signal is collected and analyzed by a highly sensitive detector, accurately reflecting the distribution of tiny nanometer-scale defects on the wafer surface.

[0038] The generated laser beams include oblique incident beams and vertical incident beams. These two types of laser beams can collect scattered light signals of different defect types at the same wafer location, thereby achieving a balance between detection efficiency and defect coverage.

[0039] In the prior art, in order to obtain the above-mentioned two-beam system, a beam splitter prism is usually used at the laser exit to split the incident light beam into a vertical incident light beam and an oblique incident light beam. In addition, other functional devices are configured in the above-mentioned two incident light beams, such as beam expanders, shaping lenses, and focusing lenses. However, in actual use, the applicant found that because the above-mentioned functional devices usually use the same type of lens or lens group, they are configured separately in the two incident light beams, which increases the size of the equipment and the basic cost. In addition, the two incident light beams need to be assembled and debugged separately, which also leads to problems such as reduced light energy utilization and a cumbersome and complicated debugging process.

[0040] Based on the above technical background and in order to solve the above technical problems, this embodiment provides a detection system, which integrates the oblique incident light beam and the vertical incident light beam through the optical path structure setting, reducing the problem of increased cost caused by the separate configuration of multiple functional devices, and the oblique incident light beam and the vertical incident light beam share the same set of functional devices, thereby reducing the difficulty of system assembly and debugging, thereby solving technical problems such as reduced light energy utilization and complex debugging process.

[0041] For details about its structure, please refer to Figure 1 An inspection system 100, applied to wafer inspection, includes a first incident light beam 110, an adjustment lens assembly 120, and a vertical lens assembly 130. The first incident light beam is the original incident light beam of the system, generated by a light source. The adjustment lens assembly, optionally disposed along the propagation path of the first incident light path, is designed as a light-reflecting optical device or optical device assembly, and functions to modify the propagation path of the first incident light path to form a reflected light path as needed.

[0042] The vertical mirror assembly, located along the reflected light path, is designed as an optical device or group of optical devices capable of reflecting light. Its function is to further alter the reflected light path and project it onto the surface of the wafer to be inspected, forming a second incident light beam 140 with the same optical conditions as the first incident light beam but at a different angle of incidence. The aforementioned adjustment mirror assembly and vertical mirror assembly are only used to alter the light path and do not alter the optical characteristics.

[0043] In this embodiment, the first incident light beam is the original light path, and its incident angle relative to the wafer to be inspected is an oblique incident angle. However, after the second incident light beam is adjusted by the lens assembly and the vertical lens assembly, its incident angle relative to the wafer to be inspected 200 is a vertical incident angle. It can be understood that, in this embodiment, the incident angle of the incident light beam in the inspection system can be changed by adjusting the lens assembly and the vertical lens assembly.

[0044] In this embodiment, the incident light beams corresponding to the first incident light path and the second incident light path are both projected onto the same position on the wafer to be inspected, generating corresponding first and second incident light spots. It can be understood that in this embodiment, the first and second incident light paths can be switched by adjusting the lens assembly, and the corresponding normal incident light is generated by the vertical lens assembly, thereby forming a corresponding inspection light spot on the wafer to be inspected.

[0045] Controlling whether the adjustment mirror assembly is positioned on the propagation path of the first incident light beam is achieved by adjusting the spatial height position of the adjustment mirror assembly. It is worth noting that in this embodiment, the spatial position is based on the wafer to be inspected, and the spatial height position of the adjustment mirror assembly refers to the height position relative to the wafer to be inspected.

[0046] Specifically, the adjustment mirror assembly includes at least two height positions, wherein the first height position is a height position for placing the adjustment mirror assembly into the propagation path of the first incident light beam, and at least one remaining height position is a height position for removing the adjustment mirror assembly from the propagation path of the second incident light beam. It can be understood that, depending on the beam type, the adjustment mirror assembly can be placed into or removed from the propagation path of the first incident light beam by controlling the adjustment mirror assembly to the first or second height position. It is worth noting that the height change of the adjustment mirror assembly is achieved by external power, including but not limited to power components such as motors and pneumatic devices.

[0047] In one possible implementation, the adjustment lens assembly in this embodiment is designed to be selectively configured in the first incident light path to adjust the angle of incidence of the first incident light beam. Since the original incident state of the first incident light beam is incident at an oblique angle relative to the wafer to be inspected, it can be understood that when the adjustment lens assembly is configured in the first incident light beam, the oblique angle of incidence of the first incident light beam can be changed. By arranging the second lens assembly on the beam with the changed light propagation direction, the light propagation path is changed to form a second incident light beam that is incident perpendicularly to the wafer to be inspected. When the adjustment lens assembly is not configured in the first incident light beam, the first incident light beam maintains its original incident state and projects incident light at an oblique angle toward the wafer to be inspected.

[0048] In this embodiment, the flexible configuration of the adjustment lens assembly on the first incident light beam is achieved by a motion control method. That is, the adjustment lens assembly can be controlled to move into or out of the propagation path of the first incident light beam.

[0049] Please continue reading Figure 1The adjustment mirror group and the vertical mirror group include at least three reflectors. Based on the requirement of simplicity in optical path control, three reflectors are preferably used, including a first reflector 101, a second reflector 102, and a third reflector 103. The first reflector reflects the first incident light beam to the second reflector, which then reflects the first incident light beam to the third reflector. These three reflectors form an optical transmission path, forming an incident light beam at a perpendicular angle to the wafer to be inspected.

[0050] As an implementation method, the second reflector 102 and the third reflector 103 are combined into a vertical mirror group 130, and the first reflector 101 is used as an adjustment mirror group 120. The control and adjustment of the adjustment mirror group is the control and adjustment of the first reflector. Specifically, according to the requirements of the incident light beam type, the height position of the first reflector relative to the wafer to be inspected is controlled so that the first reflector is loaded into the first incident light beam propagation path or loaded away from the first incident light beam propagation path. When the first reflector is loaded into the first incident light beam propagation path, the first incident light beam is reflected to the vertical mirror group, and a second incident light beam with a vertical incident angle is formed by the vertical mirror group to the wafer to be inspected. When the first reflector is loaded away from the first incident light beam propagation path, the first incident light beam is loaded onto the wafer to be inspected at an inclined incident angle based on the original propagation path.

[0051] Among them, the vertical mirror group in this embodiment includes a second reflector and a third reflector, wherein the second reflector is arranged on the reflected light path generated by the first reflector, and reflects the reflected light path twice to the third reflector, and forms a second incident light beam with vertical incidence through the third reflector.

[0052] In another embodiment, the first and second reflectors 101 and 102 serve as the adjustment mirror assembly 120, and the third reflector 103 serves as the vertical mirror assembly 130. By adjusting the spatial height positions of the first and second reflectors, the first or second incident light beams are controlled. Because only the controlled object is changed in this process, while the light propagation path remains unchanged, the light propagation path will not be described again.

[0053] In another possible implementation, the first reflector, the second reflector, and the third reflector are used as the same mirror group, and the switching between the first incident light beam and the second incident light beam is achieved by synchronously controlling the three mirror groups.

[0054] In this embodiment, based on the control cost and fewer interference factors in the first possible implementation, the mirror group control method in the first possible implementation is preferably selected to achieve switching between the first incident light beam and the second incident light beam by controlling the first reflector.

[0055] Please continue reading Figure 1In this embodiment, in order to ensure the uniformity of the incident light beam illumination and control multiple optical conditions such as the size of the formed spot to meet the detection requirements, at least one focusing objective lens is set on the main incident light path to achieve focal length adjustment of the light beam.

[0056] However, it is worth noting that the incident beam in this embodiment includes two incident beams, and the second incident beam is generated by changing the propagation path of the first incident beam. This optical design will cause the optical path lengths of the first and second incident beams to be inconsistent. Therefore, in this embodiment, in order to ensure that the optical path lengths of the first and second incident beams are consistent, the corresponding detection spots have the same size, shape, incident position, and energy distribution.

[0057] In this embodiment, in order to solve the above problem, the focus of the focusing objective lens is adjusted for different incident light beams by controlling the distance between the focusing objective lens and the wafer to be inspected along the optical axis.

[0058] It can be understood that for different types of incident light beams, namely the first incident light beam and the second incident light beam, the relative positions of the focusing objective lens and the wafer to be inspected are different, thereby achieving adjustment of the focal lengths corresponding to the two incident light beams, so that the first incident light beam and the second incident light beam form a first incident light spot and a second incident light spot on the wafer to be inspected with the same size, shape, incident position and the same energy distribution.

[0059] In one embodiment, the focusing lens 105 is disposed on the optical axis of the first incident light beam, and based on different types of incident light beams, the focusing lens is driven by external power to move along the optical axis to the first position or the second position. Figure 1 The direction of the arrow shown in the figure is the moving direction of the focusing lens. Figure 1 The position of the middle focusing objective lens on the first incident light beam is the first position, wherein the second position is closer to the wafer to be inspected than the first position.

[0060] Specifically, when the incident light beam is the second incident light beam, the focusing lens is driven by an external power to move along the optical axis from the first position to the second position. When the incident light beam is the first incident light beam, the focusing lens is driven by an external power to move along the optical axis from the second position to the first position.

[0061] It is worth noting that, in this embodiment, the movement of the focusing lens should be synchronized with the movement of the adjustment lens group. That is, when the position of the adjustment lens group is adjusted to the desired position, the corresponding position of the focusing lens should also be adjusted to the desired position. Therefore, in this embodiment, the adjustment lens group and the focusing lens are both connected to the same controller, which simultaneously issues adjustment commands and controls the movement of the adjustment lens group and the focusing lens to the target position based on their movement speeds.

[0062] See Figure 2 , is another embodiment of the focusing objective lens configuration. In this embodiment, the focusing objective lens is provided as a lens group, including a first focusing objective lens 105 and a second focusing objective lens 106. The first focusing objective lens is a fixed focusing objective lens and is arranged at a first position of the main incident light beam propagation path. The second focusing objective lens is an adjustable focusing objective lens, which can be selectively loaded into or out of the second position of the main incident light beam propagation path according to the type of the incident light beam. In addition, the first position and the second position are both on the optical axis of the first incident light beam, and there is a distance between the first position and the second position, and the second distance is closer to the wafer to be inspected than the first distance.

[0063] Specifically, when the current incident beam type is the first incident beam, the second focusing objective lens is controlled to be separated from the incident beam, and only the first focusing objective lens is arranged on the optical axis of the incident beam, and the first incident beam is focused by the first focusing objective lens. When the incident beam type is the second incident beam, the second focusing objective lens is controlled to be loaded into the incident beam, and the first focusing objective lens and the second focusing objective lens are arranged on the optical axis of the incident beam, and the second incident beam is focused by the two focusing objective lenses.

[0064] The loading and unloading control of the second focusing objective lens is the same as the adjustment control of the adjustment lens group, and is achieved by adjusting the height of the second focusing objective lens. Specifically, when the second focusing objective lens is required to load the incident light beam, the second focusing objective lens is adjusted from the first height to the second height so that the second focusing objective lens is configured in the incident light beam; when the second focusing objective lens is required to be unloaded from the incident light beam, the second focusing objective lens is adjusted from the second height to the first height. It is worth noting that the first and second heights of the focusing objective lens in this embodiment are based on the wafer to be inspected. The movement path of the second focusing objective lens can be referred to as the arrow in the figure.

[0065] As can be seen from the above, unlike the first embodiment, this embodiment does not require adjustment of the focusing lens along the optical axis. Instead, focal length adjustment is achieved by placing another focusing lens on the second incident beam. However, the principle of this solution is the same as that of the previous embodiment: the focal length is changed by adjusting the distance of the focusing lens relative to the wafer to be inspected.

[0066] It is worth noting that the loading and unloading of the second focusing lens in this embodiment also needs to be synchronized with the loading and unloading of the adjustment lens assembly. Similarly, the second focusing lens and the adjustment lens assembly should both be communicatively connected to the same controller, which simultaneously issues adjustment commands and controls the movement of the adjustment lens assembly and the second focusing lens to the target position based on the movement speeds of the adjustment lens assembly and the second focusing lens.

[0067] See Figure 3 In another possible implementation, the detection system is further provided with a functional optical lens group 140 on the main incident beam, which is used to adjust the optical state of the main incident beam so that the excited first incident beam and the second incident beam meet the needs of wafer detection.

[0068] Specifically, the functional optical lens assembly is sequentially provided with a polarizer 141, a beam expander 142, and a shaper 143 based on the light propagation path. The polarizer is used to change the polarization state of the incident light beam, and the beam expander and shaper are used to change the shape and size of the incident light beam.

[0069] See Figure 4 , also provides an implementation method for reducing the spatial configuration problem of the overall system. In this implementation method, in order to reduce the problem of excessive lateral space of the system caused by the oblique incident main beam, multiple objective lenses are provided to achieve space utilization.

[0070] Specifically, in the inspection system of this embodiment, the main incident beam is emitted by a light source positioned parallel to and above the wafer to be inspected. The propagation path of the generated main incident beam is also parallel to the wafer to be inspected. Two reflectors are provided to capture the obliquely incident first incident beam, and the aforementioned functional optical lens assembly is positioned along the reflected optical path to achieve beam adjustment.

[0071] It is worth noting that those skilled in the art should know that although Figure 3 and Figure 4 The configuration of the medium function optical lens group is based on Figure 1 The structure shown is for illustration only, but it does not mean that its functional optical lens assembly can only be configured in Figure 1 In the detection system shown. Figure 2 The detection system with the optical path structure shown in the figure has the same adaptability as the functional optical lens group and can be directly configured in Figure 2 On the first incident beam in the detection system.

[0072] Finally, although only the optical components of the objective lens and lens assembly described above are described, those skilled in the art will appreciate that the lens assembly includes not only the corresponding optical components but also the associated mechanical structures. For example, if the adjustment lens assembly is a lens barrel structure, the components include the corresponding reflectors and a motor connected to the lens barrel, which drives the lens barrel to move and thereby achieve loading and unloading.

[0073] With respect to the detection system provided in the above-described embodiment, by controlling the movement of the adjustment lens assembly along or away from the incident light beam propagation path, oblique incident light beams and vertical incident light beams with different incident angles are formed, thereby achieving adjustment for different incident modes of the incident light beam. The oblique incident light beam and the vertical incident light beam share a single main light beam, reducing system redundancy. Furthermore, by providing a focusing objective lens that can be synchronously controlled with the adjustment lens assembly, the corresponding focal lengths of the oblique incident light beam and the vertical incident light beam can be adjusted by controlling the position of the focusing objective lens on the optical axis of the incident light beam, thereby maintaining the same optical path length for the oblique incident light beam and the vertical incident light beam.

[0074] In this embodiment, a controller is further provided in the system for adjusting and controlling the spatial position of the adjustment lens group and the focusing lens, and the controller adjusts the system by executing the following steps. For details about these steps, please refer to Figure 5 In this embodiment, a detection method is configured in the controller to implement the adjustment of the detection system. The method specifically includes the following steps:

[0075] Step S51: Determine the type of the incident light beam according to the scanning period.

[0076] In this embodiment, each scanning cycle corresponds to a type of incident beam. The type of incident beam in this embodiment primarily refers to its angle of incidence with the wafer to be inspected, which can be either an oblique incident beam or a vertical incident beam. The current scanning cycle determines whether the incident beam is oblique or vertical, and the optical path of the system is controlled based on the determined incident beam type, thereby ensuring that the incident beam is projected onto the wafer surface to be inspected in the desired manner.

[0077] Step S52: Control and adjust the mirror group according to the type of the incident light beam to enter or move away from the incident light beam propagation path, and form a corresponding incident light beam.

[0078] Based on the incident beam type determined in step S51, in this embodiment, the target incident beam is generated by controlling the spatial position of the adjustment mirror assembly. The control result is to control the adjustment mirror assembly to enter or move away from the incident beam propagation path, and the control target is the height position of the adjustment mirror assembly. The adjustment logic is to configure position sensors at key positions in the system to obtain the spatial state corresponding to the current adjustment mirror assembly, where the key position refers to the boundary position corresponding to different types of incident beams. The preset type-position mapping relationship is then used to determine whether the spatial position of the adjustment mirror assembly corresponding to the current scanning cycle meets the requirements. If the requirements are met, the adjustment mirror assembly maintains the state; if not, the adjustment mirror assembly adjusts the state.

[0079] In this embodiment, for clarity and simplicity of control logic, only two height positions are set for the adjustment lens group, one is a first height position for generating an oblique incident light beam, and the other is a second height position for generating a vertical incident light beam.

[0080] Specifically, when the incident beam type corresponding to the current scanning cycle is an oblique incident beam, the position of the adjustment mirror group obtained by the sensor is used to determine whether the current position is at the first height position. If not, the adjustment mirror group is controlled to move upward to the first height position; if so, no height adjustment is performed. Conversely, when the incident beam type corresponding to the current scanning cycle is a vertical incident beam, the position of the adjustment mirror group obtained by the sensor is used to determine whether the current position is at the second height position. If not, the adjustment mirror group is controlled to move downward to the second height; if so, no height adjustment is performed.

[0081] Preferably, in another embodiment, a sensor is not provided for determining the current height position of the adjusting mirror assembly. Instead, a storage unit is configured in the controller to generate a data table to record each height control of the adjusting mirror assembly and the height information of the current scanning cycle, and automatically adjust the height after querying the table according to the change of the scanning cycle.

[0082] Step S53: Control the distance change of at least one focusing objective lens relative to the object to be detected according to the type of the incident light beam, and change the focal length of the first incident light beam or the second incident light beam.

[0083] According to the type of the incident light beam determined in step S51, in this embodiment, the focal lengths corresponding to the first incident light beam and the second incident light beam are adjusted by controlling the focusing objective lens.

[0084] Specifically, based on the determined incident beam type, the distance of the movable focusing lens relative to the wafer to be inspected is controlled along the optical axis, and the height of the adjustable focusing lens can be adjusted to move the adjustable focusing lens into or out of the incident beam propagation path.

[0085] The control of the adjustable focusing objective lens is as follows: when the incident light beam is the first incident light beam, the adjustable focusing objective lens is controlled to be moved away from the optical axis of the first incident light beam. When the incident light beam is the second incident light beam, the adjustable focusing objective lens is controlled to be loaded into the optical axis of the first incident light beam, and the position of the adjustable focusing objective lens on the optical axis is a fixed position. The loading or unloading of the adjustable focusing objective lens is achieved by controlling the height position of the adjustable focusing objective lens relative to the wafer to be inspected. The adjustable focusing objective lens has a first height position and a second height position, which correspond to the target positions for loading or unloading, respectively. The configuration of the adjustable focusing objective lens on the optical axis is achieved by controlling the adjustable focusing objective lens at the first height position or the second height position.

[0086] It is worth noting that steps S52-S53 are not a sequential processing process, but a synchronous process, that is, after determining the type of the incident light beam, the processing processes of step S52 and step S53 are performed synchronously, so that the incident angle requirements and focal length requirements of the incident light beam are met at the same time.

[0087] Another possible implementation of this embodiment further provides a defect detection device, which includes a carrier, a detector assembly, a processing center, and a detection system according to any of the above-described embodiments. The carrier is used to carry a wafer to be inspected and to move along an equidistant spiral to follow the movement of the wafer to be inspected. The detector assembly is used to receive a scattered light beam generated by an incident light beam generated by the detection system and passing through the wafer to be inspected, thereby generating a scattered light signal. The processing center is used to process the scattered light signal to obtain a detection result.

[0088] In this embodiment, the incident beam includes a first incident beam and a second incident beam, which form corresponding first and second incident light spots on the surface of the wafer to be inspected, respectively. The first and second incident light spots have the same size. The first incident beam is an oblique incident beam, and the second incident beam is a vertical incident beam. Both are formed through steps S51 to S53 based on the current scan cycle of the defect inspection equipment.

[0089] Specifically, the current scanning cycle and the type of incident beam corresponding to that scanning cycle are determined. Based on the incident beam type, the height of the mirror assembly is controlled and adjusted to a target height to achieve the configuration of the corresponding incident beam type. This incident beam type is then projected onto the wafer to be inspected, which moves along an equidistant spiral. The incident beam remains unchanged, while the wafer to be inspected moves along a specific path based on the stage. The incident beam passes through the wafer to be inspected, generating a scattered beam. A scattering signal corresponding to the scattered beam is obtained through the detector assembly. Scattering signals for all locations on the wafer to be inspected are obtained based on the complete movement of the wafer to be inspected.

[0090] After completing the scanning of all sites, the scanning cycle is configured according to the detection needs to start a new scanning cycle. And based on the new scanning cycle and the corresponding incident beam type, the height of the current adjustment mirror group is adjusted to realize the configuration of the corresponding type of incident beam, and the incident beam is changed from the type of the previous scanning cycle. If the incident beam type corresponding to the previous scanning cycle is an oblique incident beam, the incident beam type corresponding to the new stage scanning cycle is a vertical incident beam; accordingly, the adjustment mirror group is lowered by lowering the current height position so that the turntable that previously carried the incident beam propagation path is adjusted to carry the incident beam propagation path, thereby forming a vertical incident beam. The vertical incident beam is projected onto the wafer to be detected, and the scanning of all sites on the wafer to be detected is realized according to the equidistant spiral movement of the wafer to be detected. The detector also collects the scattered signals of all sites on the wafer to be detected.

[0091] In this embodiment, the detector assembly is disposed on the scattered light beam path. The scattered light beam path includes two paths: a path corresponding to a large-angle detection channel and a path corresponding to a small-angle detection channel. The detector assembly also includes two sets of detectors disposed on the two paths, one set for collecting small-angle scattered light and the other for collecting large-angle scattered light.

[0092] The splitting of the scattered light beams corresponding to the two paths is achieved using an elliptical mirror and a beam splitter. An elliptical mirror is placed on the main path of the scattered light beam, and a beam splitter is placed within the elliptical mirror. The beam splitter's reception range corresponds to the divergence range of the small-angle scattered light beam. The small-angle scattered light within the field of view is reflected by the beam splitter to a corresponding set of detectors. The scattered light beam not reflected by the beam splitter is the large-angle scattered light and is received by another set of detectors located at the light outlet of the elliptical mirror.

[0093] The two sets of detectors are respectively connected to the processing center to transmit the collected scattered light signals to the processing center.

[0094] The detection system, detection method and defect detection equipment provided in the embodiments of the present application realize switching between oblique incident light beams and vertical incident light beams by setting an adjustment mirror group capable of switching the incident light beam in the detection system, thereby reducing the size of the equipment, reducing the equipment investment cost and improving the debugging efficiency; and the same set of functional components can be used for oblique incident light beams and vertical incident light beams, thereby reducing lens processing and debugging errors and improving detection accuracy; by switching the beam setting, the disadvantage of light energy loss caused by the use of beam splitters in the prior art can be reduced, the light density at the wafer surface can be increased, and the detection sensitivity can be further improved.

[0095] See Figure 6The embodiment of the present invention further provides a readable medium 60, which stores computer-readable instructions 601. The computer-readable instructions 601 include instructions for executing the aforementioned detection method.

[0096] The functions and technical effects of the readable medium 60 provided in the embodiment of the present invention can be referred to the technical effects of the calibration method in the aforementioned embodiment, and will not be described in detail here.

[0097] It should be noted that in the several embodiments provided in this application, it should be understood that the disclosed systems, devices and / or methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units / modules is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or modules can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0098] The units / modules described as separate components may or may not be physically separate, and the components shown as units / modules may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units / modules may be selected to achieve the objectives of this embodiment according to actual needs.

[0099] In addition, the functional units / modules in various embodiments of the present invention may be integrated into a single processing unit / module, each unit / module may exist physically separately, or two or more units / modules may be integrated into a single unit / module. The aforementioned integrated units / modules may be implemented in the form of hardware or hardware plus software functional units / modules.

[0100] The above-mentioned integrated units / modules implemented in the form of software functional units / modules can be stored in a computer-readable storage medium. The above-mentioned software functional units stored in a storage medium include a number of instructions for causing one or more processors of a computer device (which can be a personal computer, server, or network device, etc.) to perform some of the steps of the methods described in various embodiments of the present invention.

[0101] The above-mentioned integrated units / modules implemented in the form of software functional units / modules can be stored in a computer-readable storage medium. The above-mentioned software functional units stored in a storage medium include a number of instructions for causing one or more processors of a computer device (which can be a personal computer, server, or network device, etc.) to perform some of the steps of the methods described in various embodiments of the present invention.

[0102] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A detection system, characterized in that: The system comprises: a main incident light beam, the main incident light beam being incident at an oblique angle to the object to be detected and forming a first incident light spot on the surface of the object to be detected; an adjusting mirror assembly, comprising at least one reflecting mirror, which can be selectively arranged on the propagation path of the main incident light beam, and is used to change the propagation direction of the main incident light beam and make the main incident light beam propagate to the vertical mirror assembly; a vertical mirror assembly, configured to change the propagation direction of the main incident light beam and form a normal incident light beam relative to the object to be detected, and form a second incident light spot on the surface of the object to be detected; At least one focusing objective lens is arranged on the propagation path of the main incident light beam, and the focal length is adjusted by controlling the distance between the focusing objective lens and the object to be detected. The first incident light spot and the second incident light spot have the same size, shape, incident position and the same energy distribution.

2. The detection system according to claim 1, characterized in that A movable focusing objective lens is provided on the propagation path of the main incident light beam, and the movable focusing objective lens can be moved along the optical axis of the main incident light beam.

3. The detection system according to claim 1, characterized in that A fixed focusing objective lens and an optionally adjustable focusing objective lens are arranged on the propagation path of the main incident light beam; the adjustable focusing objective lens follows the adjustment lens group and is optionally configured on the main incident light beam, and the adjustable focusing objective lens is arranged close to the object to be detected relative to the fixed focusing objective lens.

4. The detection system according to any one of claims 1 to 3, characterized in that: The vertical mirror group includes two oppositely arranged reflectors, one reflector is used to receive the incident light beam reflected by the adjustment mirror group and project it to the other reflector, and the other reflector is used to project the incident light beam in a normal incidence manner onto the surface of the object to be detected.

5. The detection system according to any one of claims 1 to 3, characterized in that: The adjustment mirror group includes two oppositely arranged reflective mirrors, one of which is used to receive the main incident light beam and project it to the vertical objective lens via the other reflective mirror.

6. The detection system according to claim 5, characterized in that: The vertical mirror group includes a reflecting mirror for receiving the incident light beam reflected by the adjusting mirror group and projecting the incident light beam onto the surface of the object to be inspected in a normal incidence manner.

7. The detection system according to claim 1, characterized in that A functional optical lens assembly is also provided on the main incident light beam for adjusting the optical state of the main incident light beam.

8. The detection system according to claim 7, characterized in that: The functional optical lens assembly includes a polarizer, and the polarizer is used to change the polarization state of the main incident light beam.

9. The detection system according to claim 7, characterized in that: The functional optical lens assembly includes a beam expander and a shaping lens, which are used to adjust the shape of the main incident light beam.

10. The detection system according to claim 1, characterized in that: The main incident light beam is generated by a laser light source and undergoes a propagation path change via a first reflector and a second reflector, thereby forming an incident relationship with the object to be detected at an oblique angle.

11. A detection method, characterized in that: Applied to the detection system according to any one of claims 1 to 10, the method comprising: Determine the type of incident light beam according to the scanning period; And according to the type of the incident light beam, the adjustment mirror group is controlled to enter or move away from the incident light beam propagation path, and form a corresponding first incident light beam or second incident light beam; each of the scanning cycles is only used to generate one type of incident light beam The distance change of at least one focusing objective lens relative to the object to be detected is controlled according to the type of the incident light beam, thereby changing the focal length of the first incident light beam or the second incident light beam.

12. The detection method according to claim 11, characterized in that The controlling and adjusting the mirror group to enter or move away from the incident light beam propagation path according to the incident light beam type includes: controlling and adjusting the height position of the mirror group relative to the object to be detected according to the incident light beam type.

13. The detection method according to claim 11, characterized in that The controlling the distance change of at least one focusing objective lens relative to the object to be detected according to the type of the incident light beam includes: controlling the distance of a movable focusing objective lens relative to the object to be detected along the optical axis based on the type of the incident light beam.

14. The detection method according to claim 11, characterized in that The controlling of the distance change of at least one focusing objective lens relative to the object to be detected according to the type of the incident light beam includes: adjusting the height of the adjustable focusing objective lens based on the type of the incident light beam so that the adjustable focusing objective lens is loaded into or out of the incident light beam propagation path.

15. A defect detection device, characterized in that: include: The stage is used to place the object to be inspected and moves along an equidistant spiral line; The detection system according to any one of claims 1 to 10, configured to sequentially generate a first incident light spot and a second incident light spot having the same size, shape, incident position, and energy distribution on the surface of the object to be detected based on a scanning period, and to generate corresponding first scattered light beams and second scattered light beams via the object to be detected; a detector assembly, configured to sequentially receive the first scattered light beam and the second scattered light beam, and generate corresponding scattered light signals; The processing center is used to process the scattered light signal to obtain the detection result.

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