Detection system, detection control method, defect detection equipment and detection method

Abstract

The invention relates to the technical field of semiconductor front channel detection, relates to a differential interference detection technology, and particularly relates to a detection system, a detection control method, defect detection equipment and a detection method. And the size of the formed light spot can be adjusted according to detection requirements, so that an interference signal is enhanced, and the accuracy of a detection result and the detection efficiency are improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor front-end detection technology, to differential interference detection technology, and in particular to a detection system, a detection control method, a defect detection device and a detection method. Background Art

[0002] In the existing semiconductor front-end defect detection methods, the coherent signal reflected from the sample surface can be obtained in the optical path of the differential interference contrast method. Different defect sizes, defect reflectivity differences, shapes and other characteristics will have different effects on the detection results. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a detection system, a detection control method, a defect detection device and a detection method, which can adjust the optical path of the detection system according to the detection requirements, so as to enhance the interference signal.

[0004] In the first aspect, an embodiment of the present invention provides a detection system, comprising: a beam splitting prism, which splits an incident light beam into a first beam and a second beam, the first beam and the second beam having a circular cross-section, and forming corresponding first light spots and second light spots on the surface of the object to be measured, and the first light spot and the second light spot having different polarization directions; a controller, which is used to adjust the center distance and cross-sectional size of the first light spot and the second light spot, so that the difference between the center distance between the first light spot and the second light spot and the light spot diameter is greater than the defect size, and the center distance between the first light spot and the second light spot is smaller than the light spot diameter; the defect size is determined based on the detection task.

[0005] In some specific implementations, the controller changes the center distance between the first light spot and the second light spot by adjusting the beam splitting angle of the beam splitting prism.

[0006] In some specific implementations, the beam splitting prism includes a beam splitting prism array, and the array includes a plurality of Nomarski prisms with different beam splitting angles.

[0007] In some specific implementations, an amplifier is provided in the light propagation path of the incident light beam, and the amplifier is used to expand the incident light beam so that the incident light beam has a corresponding entrance pupil diameter before entering the beam splitting prism.

[0008] In some specific implementations, the entrance pupil diameter is changed by adjusting amplification parameters of the amplifier, and the cross-sectional sizes of the first light spot and the second light spot are changed based on the change in the entrance pupil diameter.

[0009] In some specific implementations, the amplifier includes any one of a beam expander and a variable aperture.

[0010] In some specific implementations, the entrance pupil diameter is changed by adjusting the divergence angle of the beam expander.

[0011] In some specific implementations, the entrance pupil diameter is changed by adjusting the aperture of the variable iris.

[0012] In some specific implementations, the first beam and the second beam are projected onto the object surface to be measured after passing through an objective lens group, and the controller is connected to the objective lens group, and the cross-sectional sizes of the first light spot and the second light spot are changed by adjusting the focal length of the objective lens group.

[0013] In some specific implementations, a laser is further included to generate an incident light beam. The controller is connected to the laser and the cross-sectional dimensions of the first light spot and the second light spot are changed by adjusting the wavelength of the laser.

[0014] In a second aspect, a detection control method is provided, the method comprising: emitting an incident light beam; dividing the incident light beam into a first beam and a second beam, the first beam and the second beam having a circular cross-section; determining the defect size based on the detection task, and adjusting the cross-sectional size and relative position relationship of the first beam and the second beam so that the difference between the center distance between the first light spot and the second light spot formed on the surface of the object to be detected and the spot diameter is smaller than the defect size.

[0015] In some specific implementations, the adjusting the cross-sectional dimensions of the first beam and the second beam includes: adjusting the beam splitting angle, adjusting the entrance pupil diameter of the incident beam, adjusting the focal length of the objective lens group, adjusting one or more combinations of the incident beam wavelength.

[0016] In some specific implementations, adjusting the entrance pupil diameter of the incident light beam includes: adjusting the divergence angle of a beam expander.

[0017] In some specific implementations, the adjusting the entrance pupil diameter of the incident light beam includes: an iris aperture of a variable iris.

[0018] According to a third aspect, a defect detection device is provided, comprising: a processor, configured to determine a detection task, determine a target defect size based on the detection task, and send the target defect size to a controller; a controller, configured to execute any of the detection control methods described above, and based on any of the detection systems described above, emit a first light spot and a second light spot having a target size to a surface of an object to be detected, and form interference light through the surface to be detected; and a detection component, configured to receive the interference light and obtain the interference light intensity distribution in the interference light.

[0019] In some specific implementations, the interference light intensity distribution is formed by combining the interference light intensity distribution of the first light spot and the interference light intensity distribution of the second light spot.

[0020] In a fourth aspect, a defect detection method is provided, the method comprising: determining a target defect size based on a detection task; determining a target spot size of a first light spot and a second light spot based on the target defect size; emitting an incident light beam, and dividing the incident light beam into a first beam and a second beam, wherein the first beam and the second beam are beams with different polarization directions; adjusting the cross-sectional size of the first beam and the second beam to the target spot size, and forming interference light on the surface to be measured; receiving the interference light, and obtaining the interference light intensity distribution in the interference light.

[0021] In some specific implementations, determining the target defect size based on the detection task includes: determining a target defect size range based on the detection task; and obtaining a middle value of the target defect size range as the target defect size.

[0022] The embodiments of the present invention bring the following beneficial effects:

[0023] The embodiments of the present invention provide a detection system, a detection control method, a defect detection device and a detection method, which can adjust the size of the formed light spot according to the detection requirements, thereby enhancing the interference signal and improving the accuracy of the detection result and the detection efficiency.

[0024] 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 implementing the above-mentioned technology of the present disclosure.

[0025] In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. 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 creative work.

[0027] 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 numbers represent similar mechanisms in the various views of the accompanying drawings.

[0028] Figure 1A schematic diagram of light intensity distribution provided in this embodiment;

[0029] Figure 2 Another schematic diagram of light intensity distribution provided for this embodiment;

[0030] Figure 3 A schematic diagram of the structure of the detection system provided in this embodiment;

[0031] Figure 4 A schematic diagram of the detection method provided in this embodiment;

[0032] Figure 5 A schematic diagram of the structure of a defect detection device provided in this embodiment;

[0033] Figure 6 A schematic diagram of the principle optical path provided for this embodiment;

[0034] Figure 7 A schematic diagram of the defect detection method provided in this embodiment. DETAILED DESCRIPTION

[0035] In order to better understand the above technical scheme, the technical scheme 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 scheme of the present application, rather than limitations on the technical scheme 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.

[0036] In the following detailed description, numerous specific details are set forth by way of example in order to provide a comprehensive understanding of the relevant guidance. However, it will be apparent to those skilled in the art that the present application may be practiced without these details. In other cases, well-known methods, procedures, systems, compositions and / or circuits have been described at a relatively high level, without detail, in order to avoid unnecessarily obscuring aspects of the present application.

[0037] Flowcharts are used in the present application to illustrate the execution process performed by the system according to the embodiment of the present application. It should be clearly understood that the execution process of the flowchart may not be performed in order. On the contrary, these execution processes may be performed in reverse order or simultaneously. In addition, at least one other execution process may be added to the flowchart. One or more execution processes may be deleted from the flowchart.

[0038] The embodiment of the present application provides a DIC (differential interference) imaging detection system, which is applied to semiconductor front-end detection scenarios, specifically for defect detection on the surface of wafers. Among them, the working principle of the DIC detection system is to use a prism to separate the polarized incident white light into two beams of light, generally o light and e light. These two beams of light are reflected from the surface of the sample, then re-pass through the prism, and then merge. The re-merged light beams interfere to form elliptically polarized light. Through this interference, small height changes of the surface and structure of the wafer can be observed.

[0039] Among them, the "wafer" in this embodiment generally refers to a substrate formed of semiconductor or non-semiconductor materials. Examples include (but are not limited to) single crystal silicon, gallium arsenide, gallium nitride, and indium phosphide. Such substrates are typically found and / or processed in semiconductor manufacturing facilities. In some cases, a wafer may include only a substrate (i.e., a bare die). 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 dies with repeatable pattern features.

[0040] See also Figure 1 , is a detection beam and the corresponding light intensity distribution state result. Figure 1 a. The two sub-beams after polarization splitting are independent, that is, the polarized light after splitting forms two non-overlapping sub-beams. The black dots indicate the situation where defects will cause reflectivity and phase delay. In this figure, the defect is located on one sub-beam alone, and the other sub-beam does not irradiate the defect.

[0041] Based on this situation, the light intensity distribution signal can be found in Figure 1 b, Figure 1 b is the light intensity distribution generated by the interference of the two sub-beams, where the left side shows the light intensity distribution of the two sub-beams respectively. Since one of the sub-beams does not irradiate the defect, there is no light intensity loss. Therefore, the obtained interference light intensity is the interference signal on the right side of the equal sign.

[0042] See also Figure 2 , is another detection beam and the corresponding light intensity distribution state result. Figure 2 a, the two sub-beams after polarization splitting and Figure 1 The difference is that the two are in an overlapping relationship, and the corresponding defects are located at the overlapping position. That is, both sub-beams illuminate the defect position. For the light intensity distribution corresponding to this detection beam, please refer to Figure 2 b. By Figure 2 From the results of b, it can be seen that for the same defect, the light intensity signal obtained by the detection beam using this method is Figure 1 Twice the detection beam presented.

[0043] Therefore, for the detection system provided in the embodiment of the present application, based on the differential interference detection method, the relative position of the formed light spot is controlled to maximize the light intensity of the interference signal finally obtained, thereby improving the detection effect and detection efficiency.

[0044] The control logic is to control the overlap of the shaped light spots of the two sub-beams, and the overlapping area should be larger than the light spot size.

[0045] So, see Figure 3 The detection system 30 of this embodiment at least includes a beam splitting prism 32 and a controller 33 connected to the beam splitting prism. A laser 31 is also required to generate an incident light beam.

[0046] Among them, the beam splitting prism is a basic optical component of the differential interference observation method, which is used to split the incident light beam into a first beam and a second beam, and this setting has a circular cross-section, forming corresponding first light spots and second light spots on the surface of the object to be measured, that is, the surface of the wafer, wherein the first light spot and the second light spot have different polarization directions.

[0047] Specifically, in this embodiment, the first light spot is o-light, and the second light spot is e-light.

[0048] The setting of the beam splitter prism is a basic optical component in the differential interference method and will not be elaborated on here. As for the controller, it is the main component in this embodiment, which is used to adjust the cross-sectional size of the first light spot and the second light spot so that the first light spot and the second light spot overlap to form an overlapping area, and this overlapping area should be larger than the defect size.

[0049] Specifically, the controller adjusts the center distance between the first light spot and the second light spot so that the difference between the center distance and the light spot diameter is greater than the defect size, and the center distance is smaller than the light spot diameter. That is, the two light spots are overlapped by adjusting the center distance between the first light spot and the second light spot, and it is ensured that the overlapped area is larger than the defect of the wafer to be detected.

[0050] The defect size is determined based on the detection task, that is, the corresponding defect type and the size of the defect type are first determined through the detection task, and then controlled by the controller.

[0051] In this embodiment, the center distance between the o light and the e light is determined based on the following formula: y=f tanθ, where f is the focal length of the lens group, and angle θ is the separation angle of the beam splitter prism. It can be seen from this formula that, when the focal length is kept unchanged, the center distance between the first light spot and the second light spot can be adjusted by controlling the separation angle of the beam splitter prism.

[0052] Therefore, in this embodiment, the center distance between the first light spot and the second light spot is adjusted by adjusting the beam splitting angle of the beam splitting prism.

[0053] Specifically, the beam splitter prism in this embodiment includes a beam splitter prism array, not a single beam splitter prism, and each beam splitter prism in the array has a different beam splitting angle, i.e., a separation angle. The defect size is determined by the detection task, and the center distance between the first light spot and the second light spot is determined based on the defect size. Then, the separation angle range of the beam splitter prism is determined, and a beam splitter prism within the separation angle range is selected to receive the incident light beam, and form the first light spot and the second light spot with the target center distance.

[0054] In this embodiment, the movement of each beam splitting prism in the beam splitting prism array is performed based on a configured motor, that is, the motor drives the beam splitting prism to enter or leave the optical path in the detection system.

[0055] Through the above structure, the first light spot and the second light spot with the target center spacing can be obtained, but it is worth noting that the size of the light spot is larger than the defect size by default in the above structure. However, in actual situations, according to different defect types and corresponding defect sizes, the size of the light spot needs to be adjusted so that the size of the first light spot and the second light spot should be larger than the defect size.

[0056] However, it is worth noting that if only the separation angle of the beam splitter prism is adjusted, the spot size cannot be adjusted.

[0057] Therefore, in order to solve this technical problem, an optical device capable of adjusting the size of the formed light spot is also provided in the detection system.

[0058] In one embodiment, the optical device is an amplifier 34. By setting the amplifier, the incident light beam is expanded so that the incident light beam has a corresponding entrance pupil diameter and then enters the beam splitting prism array for center spacing adjustment.

[0059] The control of the amplifier changes the entrance pupil diameter by adjusting the amplification parameters of the amplifier, and the cross-sectional dimensions of the first light spot and the second light spot are changed based on the change in the entrance pupil diameter.

[0060] Specifically, the amplifier in this embodiment includes any one or more of a beam expander and a variable iris. When the beam expander is used to adjust the spot size, the entrance pupil diameter is changed by controlling the divergence angle of the beam expander; when the variable iris is used to adjust the spot size, the entrance pupil diameter is changed by controlling the iris aperture of the variable iris.

[0061] Setting an amplifier to adjust the light spot size is one implementation method, and is not the only implementation method of this embodiment. This embodiment also provides some other implementation methods to adjust the light spot size.

[0062] Specifically, according to the calculation formula of the spot diameter: It can be seen that λ is the wavelength of the incident light beam, f is the focal length of the lens group, and p is the entrance pupil diameter; the change of the spot size can be achieved by adjusting the wavelength of the incident light beam and the focal length of the lens group in addition to changing the size of the entrance pupil diameter.

[0063] Therefore, in another possible implementation, the wavelength of the incident light beam is adjusted by setting a multi-wavelength light source. Therefore, for the laser 31, a multi-wavelength laser is preferably selected in this embodiment, and the wavelength of the incident light beam is adjusted by adjusting the set wavelength of the laser.

[0064] In addition to the above-mentioned possible implementation modes, the spot size can also be adjusted by providing a zoom lens group 32 with adjustable focal length.

[0065] Specifically, a zoom lens group is arranged in front of the object to be measured, that is, behind the beam splitting prism, to adjust the focal length, thereby adjusting the size of the formed light spot.

[0066] Among them, the zoom lens group in this embodiment is an objective lens group that can change the focal length of the light beam. The change of the focal length of the incident light beam is achieved by adjusting the relative distance of the optical lenses of the objective lens group, thereby adjusting the cross-sectional size of the first light spot and the second light spot. It is worth noting that the combination of optical lenses of this objective lens group only needs to meet the requirement of adjustable focal length. The optical lens combination is not limited in this embodiment. The implementation means can be any objective lens group that can change the focal length in the existing technical solution; it can also be any optical device that can change the focal length in the existing technical solution. As long as the focal length change is met, it falls within the protection scope of this embodiment.

[0067] With respect to the above structure, it can be known that in this embodiment, at least one beam splitter prism array capable of adjusting the center distance between the first light spot and the second light spot should be included, in which a plurality of beam splitter prisms are arranged, each beam splitter prism corresponds to a different separation angle range, and the center distance between the first light spot and the second light spot is adjusted by selecting the beam splitter prism corresponding to the separation angle, so that the first light spot and the second light spot have an overlapping area; it should also include one or more devices capable of adjusting the spot size, namely an amplifier, a multi-wavelength laser and a zoom lens group, to adjust the size of the first light spot and the second light spot, so that the difference between the center distance between the first light spot and the second light spot and the spot diameter formed in the end is greater than the defect size, and the center distance between the first light spot and the second light spot is smaller than the spot diameter.

[0068] See also Figure 4 , with respect to the above detection system, a detection control method is also provided, comprising the following steps:

[0069] Step 41. Send out an incident light beam.

[0070] Step S42: Split the incident light beam into a first beam and a second beam.

[0071] In this embodiment, the first beam and the second beam may also be referred to as a first light beam and a second light beam, wherein both the first beam and the second beam have a circular cross section.

[0072] Step S43. Determine the defect size based on the detection task, and adjust the cross-sectional size and relative position relationship of the first beam and the second beam so that the difference between the center distance between the first light spot and the second light spot formed on the surface of the object to be measured and the spot diameter is greater than the defect size, and the center distance between the first light spot and the second light spot is smaller than the spot diameter.

[0073] The first light spot and the second light spot are the shaped light spots formed by the first beam / first light beam and the second beam / second light beam on the surface of the object to be tested. In this embodiment, the object to be tested is a wafer, and the surface of the object to be tested is the surface of the wafer.

[0074] In this embodiment, in this method, by controlling the molding size and spacing difference of the first light spot and the second light spot on the wafer surface, the optical information of the corresponding type of defects on the wafer surface is collected.

[0075] The cross-sectional dimensions of the first beam and the second beam are adjusted by adjusting one or more of the beam splitting angle, the entrance pupil diameter of the incident beam, the focal length of the objective lens group, and the wavelength of the incident beam.

[0076] Specifically, the center distance between the first light spot and the second light spot is achieved by adjusting the beam splitting angle, and the size change of the first light spot and the second light spot is achieved by adjusting the entrance pupil diameter, the focal length of the objective lens group and the wavelength of the incident light beam, so that the final difference between the center distance between the first light spot and the second light spot and the spot diameter is greater than the defect size, and the center distance between the first light spot and the second light spot is smaller than the spot diameter.

[0077] In one embodiment, the adjustment of the entrance pupil diameter of the incident light beam is achieved by adjusting the divergence angle of the beam expander.

[0078] In another embodiment, the adjustment of the entrance pupil diameter can also be achieved by adjusting the aperture of the variable iris.

[0079] Both of the above two implementations can be implemented as the implementation method of this embodiment, and the combination of the above two implementations can also be implemented as the implementation method of this embodiment.

[0080] See also Figure 5 For the above detection system, this embodiment also provides a defect detection device 50, which is set based on the detection system and is also configured with a processor 51 and a detector component 54.

[0081] Among them, the processor is used to determine the detection task, and determine the target defect size based on the detection task, and configure the corresponding target spot feature based on the target defect size, and send the target spot feature information to the controller in the detection system.

[0082] The controller receives the above-mentioned light spot characteristic information, and performs detection control based on step S41-step S42, and emits a shaped light spot with the target light spot characteristic to the wafer surface through the detection system, and reflects from the wafer surface to form signal light to the detector component.

[0083] The detector assembly is used to receive the generated interference light signal and obtain the interference light intensity distribution in the interference light signal.

[0084] The interference light signal received by the detector assembly is realized by the beam splitter prism 52 arranged in the reflection path, that is, the beam splitter prism allows the incident light beam to pass through and enter the beam splitter prism in the incident light path, and the reflected light passing through the beam splitter prism in the reflection light path is subjected to beam splitting processing to form reflected light that is orthogonal to the original reflection light path and is received by the detector.

[0085] Specifically, the beam splitter in this embodiment is a non-polarizing beam splitter, which realizes the beam splitting processing of the reflected light path. This solution can also use any optical device in the prior art for receiving optical signals, as long as it can process the reflected light path and enter the detector component without affecting the propagation of the incident light beam.

[0086] In addition, a polarizer 53 is provided in the reflected light path after the splitting, for forming interference light. Specifically, the polarizer has a polarization direction of 45°, and is used to generate interference light of the o-light and the e-light in this direction, so that the signal light received by the detector assembly is an interference signal, and the light intensity is the interference signal light intensity.

[0087] In this embodiment, the target light spot features are the first light spot target size and the second light spot target size, and the center distance between the first light spot and the second light spot.

[0088] The interference light intensity distribution is formed by combining the interference light intensity distribution of the first light spot and the interference light intensity distribution of the second light spot.

[0089] In this embodiment, the defect detection device performs detection based on the differential interference method, and determines the corresponding defect detection result based on the obtained interference signal intensity distribution. The interference signal intensity distribution is determined based on the field intensity distribution and the phase delay distribution.

[0090] Specifically, regarding the process of determining the light intensity distribution of the interference signal, please refer to,6, which is a schematic diagram of the detection logic of the defect detection equipment.

[0091] Among them, the xy plane is the focusing plane of the beam splitter prism or the entrance pupil plane of the objective lens, Up is the complex field distribution of the plane, and P is the aperture distribution of the plane. The uv plane is the sample plane to be detected, Uo is the complex field distribution of the o light in the plane, Ue is the complex field distribution of the e light in the plane, R is the reflection distribution of the plane, and D is the reflection phase delay distribution caused by the defects of the plane. The x'y' plane is the focusing plane of the Nomarski prism or the entrance pupil plane of the objective lens that the light path passes through after reflection.

[0092] The ξη plane is the detector surface, Uo' is the complex field distribution of the light in plane o, Ue' is the complex field distribution of the light in plane e, f is the objective lens in front of the sample, and f_detector is the condenser lens for collecting signals in front of the detector.

[0093] It is worth noting that the above views are equivalent description schematic diagrams used to conveniently express the optical path relationship. In actual scenarios, this optical path is a reflective optical path rather than a transmissive optical path.

[0094] The initial condition is that the field intensity distribution of the incident light in the xy plane is Up, which can be a Gaussian distribution or a flat-top beam. The calculation process of the complex field of the o light and e light in each plane is as follows:

[0095] Specifically, the light beam propagates from the xy plane to the uv plane, and in the absence of defects, has the following field intensity distribution:

[0096]

[0097]

[0098] ; Among them, +m and +n are the deviations of the center distance of the light spot caused by the difference in the incident angles of the o-light and the e-light introduced by the beam splitter prism.

[0099] Defects in the uv plane will introduce phase delay, which is expressed based on the following formula: Φ(u,v)=knΔ(u,v)+k[Δ h -Δ(u,v)], which is equivalent to a multiplication phase transformation:

[0100] Defects in the UV plane will also cause changes in reflectivity. In the current case, the reflected o and e light field distributions become:

[0101]

[0102]

[0103] The propagation of the light beam from the uv plane to the ξη plane is actually a one-time imaging relationship, which satisfies the Fourier integral theorem.

[0104] The reflected light path will produce a fixed phase difference because it passes through the beam splitter prism again in the reverse direction. In addition, the e-light can be processed by -m, -n again after passing through the beam splitter prism in the reverse direction, and the following e-light complex field distribution can be obtained:

[0105]

[0106]

[0107] Through the above processing, the field intensity distribution of the moral o light and e light received by the detector can be calculated, and the interference light of the o light and the e light in this direction can be generated by setting a polarizer with a 45° direction, wherein the interference light intensity calculation can be calculated using the currently calculated field intensity distribution and phase delay distribution. Regarding this calculation process, it can be implemented based on the solution in the prior art and will not be repeated in the embodiments of this application.

[0108] See also Figure 7 Based on the above defect detection device, this embodiment is also equipped with a detection method, including the following steps:

[0109] Step S71: Determine the target defect size based on the inspection task.

[0110] Step S72: Determine the target spot sizes of the first light spot and the second light spot based on the target defect size.

[0111] Step S73: emit an incident light beam, and split the incident light beam into a first beam and a second beam, wherein the first beam and the second beam are beams with different polarization directions.

[0112] Step S74: adjusting the cross-sectional dimensions of the first beam and the second beam to a target spot size, and forming interference light on the surface to be measured.

[0113] Step S75: Receive the interference light, and obtain the interference light intensity distribution in the interference light.

[0114] In this embodiment, the detection task is the defect type and the corresponding defect size range. The detection task is configured based on the front end, which can be understood as the detection instruction issued to the processor, and this detection instruction contains the target defect size. The construction of the detection task is based on all defect types and corresponding defect sizes obtained in the actual scene. This actual scene is not limited to all defect data recorded by this defect detection device, but also includes the defect data recorded in other defect detection devices and possible defect data obtained by reasoning. Therefore, the detection task includes all actual and possible defect types and corresponding defect size data in the actual scene.

[0115] Regarding how to determine the inspection task, there are automatic mode and manual mode. The automatic mode is to select the defect type, which has been configured with the corresponding defect size range, so as to automatically generate the corresponding inspection task. The manual mode is to manually select the defect size range to be detected for determination, but the manual mode also includes setting strategies to determine the upper and lower limit ratios of the inspection task. This ratio can reduce the problem of inaccurate inspection results caused by manually selecting the defect size range that is too large or too small.

[0116] In this embodiment, the target defect size is determined based on the defect size range in the instruction through the received detection task instruction. Because the defect configured in the detection task is range data, it is necessary to convert this range data into numerical data when determining the target defect size. The specific processing method is to use the middle value of the target defect size range as the target defect size, and determine the corresponding target spot size of the first light spot and the second light spot based on this target defect size. Finally, based on this target spot size, the wafer to be inspected is scanned to obtain interference light, and defect detection is performed according to the interference light intensity distribution of the interference light.

[0117] The embodiments of the present application provide a detection system, a detection control method, a defect detection device and a detection method, which can adjust the size of the formed light spot according to the detection requirements, thereby enhancing the interference signal and improving the accuracy of the detection result and the detection efficiency.

[0118] It is noteworthy that the processor in the present embodiment includes any processing element known in the art. In this sense, the processor may include any microprocessor-type device configured to execute algorithms and / or instructions. In one embodiment, one or more processors may be composed of a desktop computer, a large computer system, a workstation, an image computer, a parallel processor, or any other computer system (e.g., a networked computer), which is configured to execute a program configured to operate the system / device as described throughout this disclosure. It should be further recognized that the term "processor" can be broadly defined to cover any device having one or more processing elements that execute program instructions from a non-temporary memory medium. Therefore, the above description should not be interpreted as a limitation of the present invention but is merely an illustration.

[0119] The memory medium may include any storage medium known in the art that is suitable for storing program instructions that can be executed by the associated one or more processors. By way of non-limiting example, the memory medium may include a non-transitory memory medium. By way of additional non-limiting example, the memory medium may include, but is not limited to, a read-only memory, a random access memory, a magnetic or optical storage device (e.g., a disk), a tape, a solid-state drive, and the like. It should be further noted that the memory may be housed in a common controller housing with one or more processors. In an alternative embodiment, the memory may be remotely located relative to the physical location of the one or more processors and the controller. For example, one or more processors of the controller may access a remote memory (e.g., a server) that may be accessed through a network (e.g., the Internet, an intranet, etc.).

[0120] Those skilled in the art will recognize that the components, operations, devices, objects, and accompanying discussions described herein are used as examples for conceptual clarity, and various configuration modifications are contemplated. Therefore, as used herein, the specific examples and accompanying discussions set forth are intended to represent their more general class. In general, the use of any specific example is intended to represent its class, and the non-inclusion of specific components, operations, devices, and objects should not be considered limiting.

[0121] With respect to the use of substantially any plural and / or singular terms herein, those skilled in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. For clarity, the various singular / plural arrangements are not explicitly set forth herein.

[0122] The subject matter described herein sometimes illustrates different components contained in or connected to other components. It should be understood that such depicted architectures are exemplary only, and in fact many other architectures that achieve the same functionality can be implemented. In a conceptual sense, any arrangement of components that achieve the same functionality is effectively "associated" so that the desired functionality is achieved. Therefore, any two components combined to achieve a specific functionality herein can be considered to be "associated" with each other so that the desired functionality is achieved, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be considered to be "connected" or "coupled" to each other to achieve the desired functionality, and any two components that can be so associated can also be considered to be "coupleable" to each other to achieve the desired functionality. Specific examples that can be coupled include, but are not limited to, components that can physically cooperate and / or physically interact and / or components that can interact and / or interact wirelessly and / or components that interact and / or interact logically.

[0123] In addition, it should be understood that the present invention is defined by the appended claims. It will be understood by those skilled in the art that, in general, the terms used herein and particularly in the appended claims (e.g., the body of the appended claims) are generally intended to be "open" terms (e.g., the term "including" should be interpreted as "including but not limited to", the term "having" should be interpreted as "at least having", the term "include" should be interpreted as "including but not limited to", etc.). It should be further understood by those skilled in the art that if there is an intention to express the introduced technical solution elements as a specific number, then this intention will be explicitly stated in the technical solution, and when there is no such statement, there is no such intention. For example, as an aid to understanding, the following appended claims may contain the use of the introductory phrases "at least one" and "one or more" to introduce the technical solution elements. However, the use of such phrases should not be taken as implying that a solution element introduced by the indefinite article "a" or "an" limits any particular solution containing the introduced solution element to inventions containing only one of the elements, even when the same solution includes the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" or "an" should generally be interpreted as meaning "at least one" or "one or more"); the same is true for the use of definite articles used to introduce solution elements. In addition, even if a specific number of introduced solution elements is explicitly recited, a person skilled in the art will recognize that the recitation should generally be interpreted as meaning at least the recited number (e.g., an explicit recitation of "two elements" without other modifiers generally means at least two elements, or two or more elements). Furthermore, in those instances where a convention similar to “at least one of A, B, and C, etc.” is used, generally speaking, this construction is intended to mean that one skilled in the art will understand the meaning of the convention (e.g., “a system having at least one of A, B, and C” will include, but is not limited to, systems having only A, only B, only C, both A and B, both A and C, both B and C, and / or both A, B, and C, etc.). In those instances where a convention similar to “at least one of A, B, or C, etc.” is used, generally speaking, this construction is intended to mean that one skilled in the art will understand the meaning of the convention (e.g., “a system having at least one of A, B, or C” will include, but is not limited to, systems having only A, only B, only C, both A and B, both A and C, both B and C, and / or both A, B, and C, etc.).It will be further understood by those skilled in the art that any transitional word and / or phrase (whether in the specification, claims or drawings) that indicates two or more alternative terms should be understood to include the possibility of one, any or both of the terms. For example, the phrase "A or B" should be understood to include the possibility of "A" or "B" or "A and B".

[0124] It is believed that many of the advantages of the present disclosure and its attendant advantages will be appreciated from the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of components without departing from the disclosed subject matter or sacrificing all of its material advantages. The forms described are merely illustrative, and it is intended that such changes be covered and included by the appended claims. Furthermore, it should be understood that the invention is defined by the appended claims.

Claims

1. A detection system, characterized in that: include: A beam splitting prism, which splits an incident light beam into a first beam and a second beam, wherein the first beam and the second beam have circular cross sections and form corresponding first light spots and second light spots on the surface of the object to be measured, and the first light spots and the second light spots have different polarization directions; A controller is used to adjust the center distance and cross-sectional size of the first light spot and the second light spot so that the difference between the center distance and the spot diameter of the first light spot and the second light spot is greater than the defect size, and the center distance between the first light spot and the second light spot is smaller than the spot diameter; the defect size is determined based on the detection task.

2. The detection system according to claim 1, characterized in that: The controller changes the center distance between the first light spot and the second light spot by adjusting the beam splitting angle of the beam splitting prism.

3. The detection system according to claim 2, characterized in that: The beam splitting prism comprises a beam splitting prism array, wherein the array comprises a plurality of Nomarski prisms or Wollaston prisms with different beam splitting angles.

4. The detection system according to claim 1, characterized in that: An amplifier is arranged in the light propagation path of the incident light beam, and the amplifier is used to expand the incident light beam so that the incident light beam has a corresponding entrance pupil diameter and then enters the beam splitting prism.

5. The detection system according to claim 4, characterized in that: The entrance pupil diameter is changed by adjusting the amplification parameters of the amplifier, and the cross-sectional sizes of the first light spot and the second light spot are changed based on the change of the entrance pupil diameter.

6. The detection system according to claim 5, characterized in that: The amplifier includes any one of a beam expander and a variable iris.

7. The detection system according to claim 6, characterized in that: The entrance pupil diameter is changed by adjusting the divergence angle of the beam expander.

8. The detection system according to claim 6, characterized in that: The entrance pupil diameter is varied by adjusting the iris aperture of the variable iris.

9. The detection system according to claim 1, characterized in that: The first beam and the second beam are projected onto the surface of the object to be measured after passing through the objective lens group. The controller is connected to the objective lens group, and the cross-sectional dimensions of the first light spot and the second light spot are changed by adjusting the focal length of the objective lens group.

10. The detection system according to claim 1, characterized in that: It also includes a laser for generating an incident light beam. The controller is connected to the laser and the cross-sectional dimensions of the first light spot and the second light spot are changed by adjusting the wavelength of the laser.

11. A detection control method, characterized in that: The method comprises: Send out an incident light beam; Splitting the incident light beam into a first beam and a second beam, the first beam and the second beam having circular cross-sections; The defect size is determined based on the detection task, and the cross-sectional size and relative position relationship of the first beam and the second beam are adjusted so that the difference between the center distance between the first light spot and the second light spot formed on the surface of the object to be detected and the spot diameter is greater than the defect size, and the center distance between the first light spot and the second light spot is less than the spot diameter.

12. The detection control method according to claim 11, characterized in that: The adjusting of the cross-sectional dimensions of the first beam and the second beam comprises: adjusting one or more combinations of the following: adjusting the beam splitting angle, adjusting the entrance pupil diameter of the incident beam, adjusting the focal length of the objective lens group, and adjusting the wavelength of the incident beam.

13. The detection control method according to claim 12, characterized in that: The adjusting the entrance pupil diameter of the incident light beam comprises: adjusting the divergence angle of the beam expander.

14. The detection control method according to claim 12, characterized in that: The step of adjusting the entrance pupil diameter of the incident light beam comprises: adjusting the aperture of the variable iris.

15. A defect detection device, characterized in that: include: A processor, configured to determine a detection task, determine a target defect size based on the detection task, determine a target light spot feature based on the target defect size, and send the target light spot feature information to a controller; A controller, configured to execute the detection control method according to any one of claims 11 to 14, and based on the detection system according to any one of claims 1 to 10, emit a first light spot and a second light spot having target light spot characteristics to the surface of the object to be detected, and form interference light through the surface to be detected; The detection component is used to receive the interference light and obtain the interference light intensity distribution in the interference light.

16. The defect detection device according to claim 15, characterized in that: The interference light intensity distribution is formed by combining the interference light intensity distribution of the first light spot and the interference light intensity distribution of the second light spot.

17. A defect detection method, characterized in that: The method comprises: Determine the target defect size based on the inspection task; Determining target spot sizes of the first light spot and the second light spot based on the target defect size; Emits an incident light beam, and divides the incident light beam into a first beam and a second beam, wherein the first beam and the second beam are beams with different polarization directions; Adjusting the cross-sectional dimensions of the first beam and the second beam to a target spot size and forming interference light on the surface to be measured; The interference light is received, and the interference light intensity distribution in the interference light is acquired.

18. The defect detection method according to claim 17, characterized in that: The determining of the target defect size based on the detection task includes: Determining a target defect size range based on the inspection task; The middle value of the target defect size range is obtained as the target defect size.

Images