Detection system

Abstract

The invention discloses a detection system, and belongs to the field of wafer detection. The detection system comprises a first light source assembly used for generating a first detection light beam to form a first detection light spot for bright field detection; the second light source assembly is used for generating a second detection light beam to form a second detection light spot for dark field detection; in bright field detection, a detected object generates normal reflected light under the action of a first detection light spot, and the normal reflected light sequentially passes through a signal light collector and a beam splitter and then reaches a first optical filter to selectively receive light beams from the beam splitter, so that a polarized line detector receives the reflected light; in dark field detection, the detected object generates normal scattered light under the action of the second detection light spot, and the normal scattered light sequentially passes through the signal light collector and the beam splitter and then reaches the second light filter to selectively receive light beams from the beam splitter, so that the line detector receives the scattered light. Light and dark field detection can be simultaneously carried out on the detected object, and the efficiency is improved.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application number 201810954898.4, application date August 21, 2018, and invention name “Wafer Defect Detection System and Method”. Technical Field

[0002] The present invention relates to the field of wafer detection, and in particular to a detection system. Background Art

[0003] Wafer defect detection involves inspecting the wafer for defects such as grooves, particles, and scratches, as well as their locations. Wafer defect detection has a wide range of applications. On the one hand, as the chip substrate, defects on the wafer can cause the expensive manufacturing process to fail. Wafer manufacturers often perform defect detection to ensure product quality, and wafer users also need to ensure the cleanliness of the wafer before use to ensure product quality. On the other hand, because semiconductor processing requires strict control over additional contamination during the process, and direct monitoring of additional contamination during the process is difficult, the degree of additional contamination in the process is often determined by comparing defects before and after wafer processing. Consequently, various wafer defect detection methods have been explored.

[0004] Currently, common wafer defect detection methods primarily fall into two categories: electron beam testing and optical testing. Thanks to the extreme wavelength of electron waves, electron beam testing enables direct imaging with a resolution of 1 to 2 nanometers. However, it takes a long time and requires a high vacuum environment, making it typically used for spot checks on a few critical circuit components. Optical testing, a general term for methods that utilize the interaction of light and the chip, determines the presence and size of defects by scanning to detect the presence and intensity of both incident light and scattered light from the defect. Summary of the Invention

[0005] Aiming at the defects of current optical measurement methods, such as long time consumption and low precision, the present invention proposes a system capable of performing multi-incident angle detection on wafers.

[0006] On the one hand, a detection system is provided, comprising a first light source assembly (410), a second light source assembly (420), a signal light collector (435), a beam splitter (436), a first filter (437), a polarization line detector (440), a second filter (438), and a line detector (441); The first light source assembly (410) is used to generate a first detection light beam, the first detection light beam is used to form a first detection light spot, and the first detection light spot is used for bright field detection; the second light source assembly (420) is used to generate a second detection light beam, the second detection light beam is used to form a second detection light spot, and the second detection light spot is used for dark field detection; wherein the wavelength of the first detection light beam is different from the wavelength of the second detection light beam; In bright field detection, the object to be measured generates reflected light in the normal direction under the action of the first detection light spot, and the reflected light passes through the signal light collector (435) and the beam splitter (436) in sequence and reaches the first filter (437). The first filter (437) selectively receives the light beam from the beam splitter (436), so that the polarization line detector (440) receives the reflected light in the normal direction generated by the object to be measured under the action of the first detection light spot; In dark field detection, the object under test generates scattered light in the normal direction under the action of the second detection light spot, and the scattered light passes through the signal light collector (435) and the beam splitter (436) in sequence and reaches the second filter (438). The second filter (438) selectively receives the light beam from the beam splitter (436), so that the line detector (441) receives the scattered light in the normal direction generated by the object under test under the action of the second detection light spot.

[0007] Optionally, the detection system further comprises a signal light collecting device (439) and another line detector (442); In dark field detection, the object under test also generates illegal upward scattered light under the action of the second detection light spot, and the light passes through the signal light collecting device (439) to reach the other line detector (442), so that the other line detector (442) receives the illegal upward scattered light generated by the object under test under the action of the second detection light spot.

[0008] Optionally, the detection system further comprises another beam splitter (433), and the first detection light beam passes through the other beam splitter (433) and is incident on the object to be detected from a normal direction to form the first detection light spot; The object under test generates the reflected light in the normal direction under the action of the first detection light spot and generates the scattered light in the normal direction under the action of the second detection light spot. After passing through the signal light collector (435), the reflected light first reaches the other beam splitter (433) and then reaches the beam splitter (436).

[0009] Optionally, after reaching the other beam splitter (433), the first detection light beam is reflected by the other beam splitter (433) to be incident on the object to be measured from the normal direction to form the first detection light spot; The object under test generates the reflected light in the normal direction under the action of the first detection light spot and generates the scattered light in the normal direction under the action of the second detection light spot. After reaching the other beam splitter (433), the other beam splitter (433) allows the scattered light to be transmitted to the beam splitter (436).

[0010] Optionally, the detection system further comprises an aperture (431) and a polarizer (432); the first detection light beam passes through the aperture (431) and the polarizer (432) in sequence before reaching the other beam splitter (433).

[0011] Optionally, the detection system further comprises a shaping lens group (434); after the second detection light beam passes through the shaping lens group (434), it is shaped by the shaping lens group (434) so ​​as to be incident on the object to be detected from an illegal upward direction to form the second detection light spot.

[0012] Optionally, the object under test generates reflected light in the normal direction under the action of the first detection light spot and generates scattered light in the normal direction under the action of the second detection light spot. After reaching the beam splitter (436), the beam splitter (436) allows part of the light to reach the first filter (437) through transmission and part of the light to reach the second filter (438) through reflection.

[0013] Optionally, the first detection light spot is a linear light spot; and / or the second detection light spot is a linear light spot.

[0014] Optionally, the first detection light spot and the second detection light spot at least partially overlap.

[0015] Optionally, after the first light source assembly (410) generates a first detection beam and the second light source assembly (420) generates a second detection beam, and respectively forms a first detection light spot and a second detection light spot, the object to be measured is irradiated by the first detection light spot and the second detection light spot at the same detection position at the same time, thereby generating normal reflected light and normal scattered light under the action of the first detection light spot and the second detection light spot, respectively, and reaching the beam splitter (436) through the signal light collector (435), and the beam splitter (436) splits the received light beam so that it reaches The first filter (437) and the second filter (438) are connected, the first filter (437) selectively receives the light beam from the beam splitter (436) so that the polarization line detector (440) receives the reflected light in the normal direction generated by the object under test under the action of the first detection light spot, and the second filter (438) selectively receives the light beam from the beam splitter (436) so that the line detector (441) receives the scattered light in the normal direction generated by the object under test under the action of the second detection light spot, thereby realizing synchronous detection of bright and dark fields.

[0016] By adopting the technical solution of the present invention, the area of ​​each scan can be increased, which saves wafer movement time and significantly increases detection speed. In addition, it can also perform bright field and dark field detection on the object to be tested, improving efficiency. By using the technical solution of the present invention, different particles can be detected using the same wavelength light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The embodiments are shown and explained with reference to the accompanying drawings. These drawings are used to illustrate the basic principles and only show the aspects necessary for understanding the basic principles. These drawings are not to scale. In the drawings, the same reference numerals represent similar features.

[0018] Figure 1 is a diagram of the detection system architecture according to an embodiment of the present invention; Figure 2a is an optical architecture diagram of a detection system according to an embodiment of the present invention; Figure 2b Schematic diagram of the imaging-type collection principle according to an embodiment of the present invention; Figure 3 is a schematic diagram of a scanning trajectory according to an embodiment of the present invention; Figure 4 FIG. 4 is a diagram of a detection system architecture according to another embodiment of the present invention. DETAILED DESCRIPTION

[0019] In the following detailed description of preferred embodiments, reference will be made to the accompanying drawings, which form a part of the present invention. The accompanying drawings illustrate, by way of example, specific embodiments that can implement the present invention. The illustrative embodiments are not intended to be exhaustive of all embodiments according to the present invention. It will be understood that other embodiments may be utilized, and structural or logical modifications may be made, without departing from the scope of the present invention. Therefore, the following detailed description is not restrictive, and the scope of the present invention is defined by the appended claims.

[0020] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0021] First, the terms involved in this invention are explained. The detection beam refers to the light beam generated by the light source assembly and ultimately forms the detection spot. The angle of incidence refers to the angle between the detection beam and the surface normal of the object being measured (e.g., a wafer). The detection area is the illumination area corresponding to the signal light received by the detector. For example, the portion of the detection spot illumination area with relatively strong light intensity is received by the detector to analyze the object being measured.

[0022] Through extensive research, the inventors discovered that when using a point light source (i.e., focusing the detection spot to the smallest possible size, with a diameter on the order of tens to hundreds of microns) for point scanning detection during wafer inspection using the light scattering method, only a point area can be detected at a time. Therefore, to increase the speed of wafer inspection, it is often necessary to increase the wafer's rotational speed and the sampling rate of the photodetector. However, the trajectory of the electrically driven rotating platform carrying the wafer requires precise control, and its rotational speed is often restricted.

[0023] Furthermore, existing dark-field inspection methods for wafer defect detection typically utilize easily processable reflectors to collect scattered light. The signal collected by the reflector includes scattered light from the wafer as well as surface noise. Based on the principle of the reflector, it is known that it is designed to collect as much scattered light as possible. Therefore, the signal collected by the reflector is often mixed with noise.

[0024] Furthermore, since the point light spot size is relatively small, the areas illuminated by the point light spot need to overlap during detection or the actual detection areas will partially overlap. This causes the same area to be illuminated twice by the point light spot. Accordingly, the signal light in the area will also be collected twice, which makes the signal processing method very complicated.

[0025] Since the reflective cup collects scattered light in a way that makes it difficult to converge scattered light from different points at different points, the existing detection method can only use a point scanning method for detection.

[0026] To address the above problems, the present invention proposes to use line scanning to realize wafer defect detection. Compared with point scanning, the area of ​​each detection is increased. Line scanning detects a line area at the same time, which can significantly improve the detection speed and reduce the instrument cost.

[0027] Depending on the incident light angle (e.g., normal incidence or oblique incidence, and the corresponding oblique incidence angle) and the signal light collection angle range (normal collection or non-normal collection), the light scattering method can be implemented in multiple ways, including: (1) normal incident illumination and normal collection; (2) normal incident illumination and non-normal collection; (3) oblique incident illumination and normal collection; (4) and oblique incident illumination and non-normal collection.

[0028] In addition, depending on the angle of the incident light and the type of defect, the scattered light will show different distribution characteristics. Specifically, for protrusion defects (such as particles) distributed on the wafer, when the light is incident normally, the defect scattered light is relatively evenly distributed in the normal and non-normal collection channels; for pit defects distributed on the wafer, when the light is incident normally, the defect scattered light is mainly distributed in the normal collection channel, and the defect scattered light collected by the non-normal collection channel is relatively weak. Similarly, for protrusion defects distributed on the wafer, when the light is incident obliquely, the defect scattered light is mainly distributed in the non-normal collection channel; for pit defects distributed on the wafer, when the light is incident obliquely, the defect scattered light is collected by the non-normal collection channel. It is understandable that for oblique incidence, when the incident angle of light changes, the corresponding scattered light distribution will also change. It is understandable that the collection channel corresponds to the exit angle of the scattered light.

[0029] As can be seen from the above, oblique incidence has higher detection sensitivity for protrusion defects, while normal incidence has higher detection sensitivity for pit defects. Therefore, defect type analysis can be performed based on the detection method and the corresponding signal distribution.

[0030] Figure 1 FIG. 4 is a diagram of the detection system architecture according to an embodiment of the present invention.

[0031] As shown in the figure, the detection system includes a light source component 101, a detection component 102, a signal collection component 103 and a processor component 104, wherein the light source component 101 provides a detection beam through a light generator (such as one or more lasers).

[0032] The detection component 102 is used to generate a detection spot corresponding to a specified incident angle based on the received detection light beam. In one embodiment, the detection component 102 can generate multiple detection spots. When the wafer is being detected (i.e., the detection spot is irradiated onto the wafer), the wafer will generate (for example, by scattering or reflection) corresponding signal light under the action of the detection spot. It can be understood that when the detection spot irradiates a defect, the signal light generated will vary according to the type of defect or other parameters. The detection component 102 also includes a machine for carrying the wafer, and the machine moves under the control of the processor component 104, and can then move the wafer according to a specified trajectory, adjust the relative position of the wafer and the detection spot, and realize scanning detection.

[0033] The signal collection component 103 includes detection branches corresponding to a plurality of scattered light collection channels, and is capable of collecting signal light generated by the line detection light spot at different angles, thereby generating corresponding detection information.

[0034] The processor component 104 determines defect characteristic information on the wafer, such as the type, location, and other parameters of the defect, based on the detection information from the signal collection component 103 .

[0035] Figure 2a FIG. 4 is an optical architecture diagram of a detection system according to an embodiment of the present invention.

[0036] As shown in the figure, the light source 201 generates a detection beam, which passes through the shaping lens group 2021 in the detection assembly to reach the wafer surface, forming a linear detection spot. It can be understood that the width and length of the linear detection spot can be controlled by the shaping lens group 2021.

[0037] In one embodiment, the detection assembly further includes a polarizer 2022 (e.g., a quarter-wave or half-wave plate) to change the polarization state of the detection beam. For example, different polarization states can be achieved for different detection beams, such as p-light, s-light, circularly polarized light, etc., as required.

[0038] When the inspection spot illuminates the wafer surface, most of the incident light will be reflected from the other side at the same angle as the incident light. If there is a defect in the illumination position, the defect will cause some light to be emitted upward at various angles in the form of scattered light. Therefore, setting up multiple scattered light collection channels at different locations to detect scattered light intensities at different angles can determine defect information at the location of the linear inspection spot. It can be understood that collecting signal light through multiple signal collection channels can improve detection accuracy.

[0039] In this embodiment, the signal light collection channel is divided into a normal collection channel P1 and non-normal collection channels P2 and P3 according to the collection angle range, wherein the collection angle range corresponding to the normal collection channel P1 is 0° to 20°, and the collection angle range corresponding to the non-normal collection channels P2 and P3 is 20° to 90°. For example, the collection angle range corresponding to the non-normal collection channel P2 is 35±10°, and the collection angle range corresponding to the non-normal collection channel P3 is 55±10°. In this embodiment, the detection branch corresponding to each collection channel includes a detection lens group and a detector to realize imaging collection of the signal light. When a line detector is used, the detection area is linear. In one embodiment, the center of the detection area coincides with the center of the detection spot, and the length of the detection area is less than the length of the detection spot. In actual applications, the light intensity at the center of the detection spot is stronger, and the light intensity at both ends is weaker. The signal light at both ends is easily submerged by noise. Therefore, the detection accuracy can be improved by setting the length of the detection area to be less than the length of the detection spot.

[0040] Figure 2b Schematic diagram of the imaging collection principle according to an embodiment of the present invention.

[0041] As shown in the figure, the detection beam illuminates the wafer surface, forming a detection spot. When a defect is present at position A, the defect, under the action of the detection spot, generates scattered light that propagates in all directions above the wafer. In this embodiment, multiple collection channels are provided in the normal and non-normal directions. Each collection channel collects scattered light spatially distributed around a specific scattering angle.

[0042] The defect at position A emits scattered light within a specific angle range, which is projected through detection lens group 21 onto the designated position of detector TCa. Similarly, when a defect at position B exists, the scattered light generated by the defect, under the influence of detection spot B, is projected through detection lens group 22 onto the designated position of detector TCb. The scattered light from the defect at position A is projected via detection lens group 22 to a position next to detector TCb. Similarly, the scattered light from the defect at position B is projected via detection lens group 21 to a position next to detector TCa. Therefore, detectors TCa and TCb independently collect the scattered light generated by the defects at positions A and B, respectively, without interfering with each other.

[0043] By making each collection channel independent of each other, multi-channel collection of signal light can be achieved when it is necessary to collect the normal and non-normal directions of the normally incident and obliquely incident light spots respectively.

[0044] Please refer to Figure 2aThe signal collection component includes first to third detection branches, wherein the first detection branch includes a line detector TC1 and a first detection lens group TJ1 to collect the signal light generated by the wafer on the normal collection channel P1 under the action of the detection spot; the second detection branch includes a line detector TC2 and a second detection lens group TJ2 to collect the signal light generated by the wafer on the non-normal collection channel P2 under the action of the detection spot; the third detection branch includes a line detector TC3 and a third detection lens group TJ3 to collect the signal light generated by the wafer on the non-normal collection channel P3 when the detection spot is in the normal collection channel.

[0045] In one embodiment, the detection area corresponding to each detection spot (i.e., the portion received by the line detector) can be set to the portion of each detection spot with the highest light intensity (a linear shape). In other words, the detector can collect signal light in a linear manner. The center of the detection area coincides with the center of the detection spot, and the length of the detection area is less than or equal to the length of the detection spot.

[0046] In one embodiment, the detection spot is linear, and the length of the detection zone is 90%-95% of the length of the detection spot. In one embodiment, the length of the detection spot is 5 mm to 10 mm, and the width is 5 μm to 100 μm.

[0047] Although Figure 2a Three detection branches are shown in FIG. 3 , but in other embodiments, other numbers of detection branches may be set according to defect characteristics of the wafer, wherein each detection branch corresponds to an incident angle different from that of other detection branches.

[0048] As can be seen above, through imaging-based collection, the signal light corresponding to each point in the detection area can be converged by the detection lens group to a designated position on the line detector. As a result, the light collected at each point on the line detector is independent of each other and directly correlated with the scattered light at the detection spot location. In this way, through the detection lens group and line detector, the relatively strong light intensity portion of the spot illumination area can be captured as a linear detection area.

[0049] Figure 3 FIG. 4 is a schematic diagram of a scanning trajectory according to an embodiment of the present invention.

[0050] As shown in the figure, the detection spot extends along the radial direction of the wafer, so that it can be scanned from the outer circle to the inner circle in a concentric circle manner.

[0051] In the initial state of detection, the detection spot is located at the outermost position of the wafer through the movement of the machine. It can be understood that this embodiment detects the entire wafer. If the area to be tested is a part of the wafer, the detection spot needs to be moved to the outermost part of the area to be tested. Then, the machine drives the wafer to rotate, and the signal light scattered by the wafer is collected in the normal and non-normal directions at the same time through the signal collection component. After completing one circle along the first concentric circle, the machine drives the wafer to move so that the detection spot moves a distance d in the first radial direction (that is, the distance between the centers of adjacent concentric circles is d) for the next circle of scanning. And so on, until the detection along the Nth concentric circle is completed (at this time, the light spot is irradiated to the center of the wafer), thereby completing the scanning of the wafer and obtaining a set of detection information corresponding to the detection spot. It can be understood that after each circle, the scanning of an annular area can be completed. In one embodiment, the moving distance d is greater than or equal to 80% of the length of the detection spot and less than or equal to the length of the detection spot.

[0052] In this embodiment, the detection area of ​​the detection spot extends in the radial direction, and the scanning direction of the detection spot is perpendicular to the extension direction of the detection spot. It is understood that in another embodiment, the angle between the scanning direction of the detection spot and the extension direction of the detection spot is greater than 0 and less than 90°.

[0053] Although the above embodiment detects from the outer circle to the inner circle of the wafer, it is understood that in another embodiment, scanning can also be performed from the inner circle to the outer circle. In addition, the detection spot can extend along the radial direction of the wafer or in other directions. The wafer scanning path can also be spiral, Z-shaped, S-shaped, rectangular, etc. For example, when using a spiral trajectory scanning, the mobile platform rotates while slowly translating in one direction to complete the scanning of the entire area.

[0054] Therefore, when the detection areas do not overlap with each other, multiple detection spots can be set to detect the wafer, and the multiple detection spots can partially overlap or not overlap with each other.

[0055] As can be seen from the above, for pit-type defects, using normal incidence can achieve better detection accuracy, while oblique incidence light source detection can achieve high-precision detection of protrusion-type defects. Therefore, the detection system can not only use vertical incidence and oblique incidence alone, but also use a solution that uses both vertical and oblique incidence light for detection. To distinguish between vertical and oblique incidence scattered light, a wavelength separation method can be used, that is, different wavelengths of light sources are used for vertical and oblique incidence detection.

[0056] Figure 4 This is a diagram of the detection system architecture according to another embodiment of the present invention. Through this detection system, bright field and dark field synchronous detection can be achieved.

[0057] As shown in the figure, first light source assembly 410 generates a first detection beam, which passes through aperture 431, polarizer 432, and beam splitter 433 to reach the wafer surface, forming a first detection spot S1. Second light source assembly 420 generates a second detection beam, which passes through shaping lens assembly 434 to reach the wafer surface, forming a detection spot S2 that at least partially overlaps with detection spot S1. In one embodiment, detection spot S2 is a linear spot, which can maximize the light intensity in a dark field.

[0058] For brightfield detection, the wafer generates corresponding reflected light under the action of the first detection spot S1. This light passes through the signal light collector 435 (for example, a detection lens assembly or other element with imaging collection capabilities), the beam splitter 433, and reaches the beam splitter 436. In the normal direction, the first filter 437 selectively receives the light beam from the beam splitter 436, allowing the polarization line detector 440 to receive the reflected light generated by the first detection spot S1, thus achieving brightfield detection.

[0059] In dark field, the wafer generates scattered light in both normal and illegal directions under the influence of detection spot S2. The scattered light generated in the normal direction passes through signal light collector 435 and beam splitter 433, reaching beam splitter 436. Second filter 438 selectively receives the light beam from beam splitter 436, allowing line detector 441 to receive the normal scattered light based on the second detection spot S2. The scattered light generated in the illegal direction passes through signal light collector 439 and reaches line detector 442.

[0060] It can be understood that when there is no need to analyze the scattered light generated by the detection spot S2 in the normal direction, the beam splitter 436 can be removed.

[0061] From the above, it can be seen that by splitting and selectively receiving the reflected light and scattered light in the normal direction, the detection system 400 can simultaneously realize the optical path of synchronous detection of bright and dark fields. In this method, bright field detection and dark field detection simultaneously realize line scanning detection, and the detection position is the same at the same time. By using light sources of different wavelengths for bright and dark fields, independent detection of different schemes is achieved.

[0062] While the above description uses the example of simultaneously generating detection light spots corresponding to two partially overlapping wavelengths, those skilled in the art will appreciate that, in other embodiments, detection light spots corresponding to multiple wavelengths and partially overlapping can also be generated, and the beams can be selectively received simply by configuring appropriate beam splitters and filters. For example, detection system 400 can further include a third light source assembly (not shown) that can generate a third detection light beam having a different wavelength from the first and second detection light beams and generate detection light spot S3. By configuring appropriate beam splitters and filters, scattered light or reflected light generated by detection light spot S3 can be selectively received.

[0063] The present invention proposes a detection method, comprising: generating a detection spot based on a detection light beam; linearly collecting signal light formed by the object to be measured under the action of the detection spot, and then generating detection information corresponding to the detection spot; and determining defect feature information of the object to be measured based on the detection information.

[0064] The present invention also proposes a detection method, comprising the following steps: generating a detection spot based on a detection light beam, wherein the detection spot includes a linear detection area; collecting signal light formed by scattering of the detection spot by the object to be measured, and then generating detection information corresponding to the detection spot; and determining defect characteristic information of the object to be measured based on the detection information formed in the detection area.

[0065] The step of collecting the signal light formed by the scattering of the detection light spot by the object to be measured includes: scanning the area to be measured of the object to be measured by moving the detection light spot relative to the object to be measured, and collecting the signal light during the scanning process.

[0066] When the area to be tested is circular, the scanning steps include: rotating the object around the center of the area to be tested; after rotating the object around the center of the area to be tested, translating the object relative to the detection spot along the diameter of the area to be tested by a specific step size; and repeating these steps until the entire area to be tested is covered by the detection spot. This separation of rotation and translation improves system stability, imaging quality, and detection accuracy.

[0067] In one embodiment, the specific step size is equal to or smaller than the size of the detection area in the translation direction.

[0068] The detection method can also be performed by the aforementioned detection system. Specifically, the detection component generates a detection spot based on the detection beam, and under the control of the processor component, the signal collection component collects signal light generated by the object under test after the detection spot is scattered by the object under test, thereby generating detection information corresponding to the detection spot; and the processor component determines defect feature information of the object under test based on the detection information obtained in the detection area.

[0069] While the above embodiment utilizes a linear spot for inspection, the inspection method of the present invention is equally applicable to point or surface spot inspection methods. It is understood that when using a point or surface spot for wafer inspection, the shaping lens assembly needs to be adjusted to form the point or surface spot. For example, a point spot can be used to inspect wafers using a spiral pattern.

[0070] Compared with traditional detection methods, the detection method of the present invention adopts line scanning. The area scanned each time is large, and the signal received by the line detector is relatively uniform. It not only saves the movement time of the wafer, but also significantly increases the detection speed and accuracy.

[0071] Therefore, although the present invention has been described with reference to specific examples, which are intended to be illustrative rather than limiting, it will be apparent to those skilled in the art that the present invention can be further described without departing from the scope of the present invention. The disclosed embodiments may be changed, added or deleted without departing from the spirit and scope of the present invention.

Claims

1. A detection system, characterized in that: It includes a first light source assembly (410), a second light source assembly (420), a signal light collector (435), a beam splitter (436), a first filter (437), a polarization line detector (440), a second filter (438), and a line detector (441); The first light source assembly (410) is used to generate a first detection light beam, the first detection light beam is used to form a first detection light spot, and the first detection light spot is used for bright field detection; the second light source assembly (420) is used to generate a second detection light beam, the second detection light beam is used to form a second detection light spot, and the second detection light spot is used for dark field detection; wherein the wavelength of the first detection light beam is different from the wavelength of the second detection light beam; In bright field detection, the object to be measured generates reflected light in the normal direction under the action of the first detection light spot, and the reflected light passes through the signal light collector (435) and the beam splitter (436) in sequence and reaches the first filter (437). The first filter (437) selectively receives the light beam from the beam splitter (436), so that the polarization line detector (440) receives the reflected light in the normal direction generated by the object to be measured under the action of the first detection light spot; In dark field detection, the object under test generates scattered light in the normal direction under the action of the second detection light spot, and the scattered light passes through the signal light collector (435) and the beam splitter (436) in sequence and reaches the second filter (438). The second filter (438) selectively receives the light beam from the beam splitter (436), so that the line detector (441) receives the scattered light in the normal direction generated by the object under test under the action of the second detection light spot.

2. The detection system according to claim 1, wherein: The detection system further includes a signal light collecting device (439) and another line detector (442); In dark field detection, the object under test also generates illegal upward scattered light under the action of the second detection light spot, and the light passes through the signal light collecting device (439) to reach the other line detector (442), so that the other line detector (442) receives the illegal upward scattered light generated by the object under test under the action of the second detection light spot.

3. The detection system according to claim 1, wherein: The detection system further comprises another beam splitter (433), and the first detection light beam passes through the other beam splitter (433) and is incident on the object to be detected from a normal direction to form the first detection light spot; The object under test generates the reflected light in the normal direction under the action of the first detection light spot and generates the scattered light in the normal direction under the action of the second detection light spot. After passing through the signal light collector (435), the reflected light first reaches the other beam splitter (433) and then reaches the beam splitter (436).

4. The detection system according to claim 3, wherein: After reaching the other beam splitter (433), the first detection light beam is reflected by the other beam splitter (433) to be incident on the object to be measured from the normal direction to form the first detection light spot; The object under test generates the reflected light in the normal direction under the action of the first detection light spot and generates the scattered light in the normal direction under the action of the second detection light spot. After reaching the other beam splitter (433), the other beam splitter (433) allows the scattered light to be transmitted to the beam splitter (436).

5. The detection system according to claim 3 or 4, characterized in that: The detection system further comprises an aperture (431) and a polarizing plate (432); the first detection light beam passes through the aperture (431) and the polarizing plate (432) in sequence before reaching the other beam splitter (433).

6. The detection system according to claim 1, wherein: The detection system further includes a shaping lens group (434); after the second detection light beam passes through the shaping lens group (434), it is shaped by the shaping lens group (434) so ​​as to be incident on the object to be detected from an illegal upward direction to form the second detection light spot.

7. The detection system according to claim 1, wherein: The object under test generates reflected light in the normal direction under the action of the first detection light spot and generates scattered light in the normal direction under the action of the second detection light spot. After reaching the beam splitter (436), the beam splitter (436) allows part of the light to reach the first filter (437) through transmission and part of the light to reach the second filter (438) through reflection.

8. The detection system according to claim 1, wherein: The first detection light spot is a linear light spot; and / or the second detection light spot is a linear light spot.

9. The detection system according to claim 1 or 8, wherein: The first detection light spot and the second detection light spot at least partially overlap.

10. The detection system according to claim 1, wherein: After the first light source assembly (410) generates a first detection beam and the second light source assembly (420) generates a second detection beam, and respectively forms a first detection light spot and a second detection light spot, the object to be measured is irradiated by the first detection light spot and the second detection light spot at the same detection position at the same time, thereby generating normal reflected light and normal scattered light under the action of the first detection light spot and the second detection light spot, respectively, and reaching the beam splitter (436) through the signal light collector (435), and the beam splitter (436) splits the received light beam so that it reaches the respective detection light spots. The first filter (437) and the second filter (438) are configured such that the first filter (437) selectively receives the light beam from the beam splitter (436) so that the polarization line detector (440) receives the reflected light in the normal direction generated by the object under test under the action of the first detection light spot, and the second filter (438) selectively receives the light beam from the beam splitter (436) so that the line detector (441) receives the scattered light in the normal direction generated by the object under test under the action of the second detection light spot, thereby realizing synchronous detection of bright and dark fields.

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