Optical detection system

Abstract

The invention discloses an optical detection system, and the system comprises a bright field illumination assembly which is used for transmitting a bright field light source to a transmission assembly; the dark field illumination assembly is used for emitting a dark field light source to a measured object; the transmission assembly is used for reflecting the bright field light source emitted by the bright field illumination assembly to a measured object and reflecting reflected light generated by the measured object based on the bright field light source back to the bright field imaging assembly; scattered light generated by the measured object based on the dark field light source is reflected back to the dark field imaging assembly; the bright field imaging assembly is used for receiving the reflected light generated by the measured object based on the bright field light source and reflected by the transmission assembly, and collecting a bright field image based on the reflected light; and the dark field imaging assembly is used for receiving the scattered light generated by the measured object based on the dark field light source and reflected by the transmission assembly, and collecting a dark field image based on the scattered light. The optical detection system can be used for optical detection of bright field illumination and dark field illumination, and compatibility of optical detection can be improved so as to adapt to various application scenes of optical detection.

Description

Technical Field

[0001] The present invention relates generally to the field of optical detection technology and more particularly to an optical detection system. Background Art

[0002] Currently, defect detection in the semiconductor industry primarily relies on automated optical inspection (AOI) systems. Specifically, AOI systems consist of an illumination system, an imaging system, sensors, and a computer system. The illumination system illuminates the object under test. The imaging system images the object, converting its optical information into image data. The sensor converts the collected optical information into digital signals, which are then transmitted to the computer system for subsequent processing to identify and detect defects.

[0003] Illumination systems can be further divided into various lighting methods, such as brightfield, darkfield, and transmitted field. Therefore, there are corresponding brightfield illumination optical inspection systems and darkfield illumination optical inspection systems. The light source of the brightfield illumination optical inspection system directly illuminates the surface of the object, and the reflected light or transmitted light directly enters the camera or sensor. This lighting method is suitable for scenes with obvious surface features and high contrast, and is particularly suitable for detecting and identifying edges, textures, and pattern features. The darkfield illumination optical inspection system is an illumination method in which only the light beam scattered by the object's particles enters the objective lens, forming a bright object image in the dark field of view. Its light source illuminates the object from a low angle, and the reflected light is excluded, allowing only scattered light to enter the camera. The background of the captured image is dark, and the edges or fine structures of the object are highlighted. This lighting method is suitable for enhancing image details in low-contrast environments and is suitable for highlighting small surface structures or defects.

[0004] Based on the above analysis, it can be seen that brightfield and darkfield optical inspection systems each have their own advantages and disadvantages. Brightfield optical inspection systems excel in scenes with high contrast and distinct surface features, and are suitable for detecting features such as edges, textures, and patterns. Darkfield optical inspection systems, on the other hand, highlight details in low-contrast environments, making them particularly suitable for detecting tiny surface structures or defects. However, few systems currently combine these two lighting methods, making it difficult for a single system to adapt to multiple application scenarios simultaneously and unable to flexibly respond to diverse inspection needs and challenges.

[0005] In view of this, there is an urgent need to provide an optical detection system to improve the compatibility of optical detection so that it can adapt to multiple application scenarios at the same time. Summary of the Invention

[0006] In order to at least solve one or more of the technical problems mentioned above, the present application proposes an optical detection system in multiple aspects to improve the compatibility of optical detection so that it can adapt to multiple application scenarios at the same time.

[0007] In a first aspect, the present application provides an optical detection system, comprising: a bright field illumination component for emitting a bright field light source to a transmission component; a dark field illumination component for emitting a dark field light source to an object to be measured; a transmission component for reflecting the bright field light source emitted by the bright field illumination component to the object to be measured, and reflecting the reflected light generated by the object to be measured based on the bright field light source back to a bright field imaging component; and for reflecting the scattered light generated by the object to be measured based on the dark field light source back to a dark field imaging component; a bright field imaging component for receiving the reflected light generated by the object to be measured based on the bright field light source reflected by the transmission component, and collecting a bright field image based on the reflected light; and a dark field imaging component for receiving the scattered light generated by the object to be measured based on the dark field light source reflected by the transmission component, and collecting a dark field image based on the scattered light.

[0008] In some embodiments, the bright field illumination assembly includes a bright field light source assembly, a first optical fiber, a first homogenizing rod, a collimating lens group, and a reflector; wherein the bright field light source emitted by the bright field light source assembly passes through the first optical fiber, the first homogenizing rod, the collimating lens group, and the reflector in sequence and is reflected to the transmission assembly.

[0009] In some embodiments, the focal length range of the collimating lens assembly is [40, 100] mm.

[0010] In some embodiments, the reflector is coated with a protective silver reflective film layer.

[0011] In some embodiments, the dark field illumination assembly includes a dark field light source assembly, a second optical fiber, a second homogenizing rod, and a relay lens group; wherein the dark field light source emitted by the dark field light source assembly passes through the second optical fiber, the second homogenizing rod, and the relay lens group in sequence and is reflected to the object to be measured.

[0012] In some embodiments, the transmission component includes a microscope objective, a dichroic mirror, a beam splitter, a tube lens group, and a double-sided reflector; wherein the bright field light source emitted by the bright field illumination component passes through the beam splitter, the dichroic mirror, and the microscope objective in sequence and is reflected to the object under test; and the reflected light generated by the object under test based on the bright field light source and the scattered light generated by the object under test based on the dark field light source pass through the microscope objective, the dichroic mirror, the beam splitter, the tube lens group, and the double-sided reflector in sequence and are reflected back to the bright field imaging component and the dark field imaging component, respectively.

[0013] In some embodiments, the transmission component further includes an autofocus sensor; wherein the autofocus sensor and the dichroic mirror are on the same horizontal line, so as to receive the light reflected by the microscope objective lens and adjust the focus according to the light.

[0014] In some embodiments, the focal length range of the tube lens group is [180, 450] mm.

[0015] In some embodiments, the double-sided reflector is coated with a protective silver reflective film layer.

[0016] In some embodiments, the bright field imaging component includes a bright field camera, which is used to receive the reflected light of the object under test generated based on the bright field light source and reflected by the transmission component, and to capture a bright field image based on the reflected light.

[0017] In some embodiments, the bright field imaging component also includes a re-inspection camera, which is used to receive the reflected light generated by the object to be measured based on the bright field light source reflected by the transmission component, and to collect a re-inspection image based on the reflected light; the transmission component also includes a dichroic prism, which is used to reflect the reflected light generated by the object to be measured based on the bright field light source reflected by the double-sided reflector to the re-inspection camera.

[0018] In some embodiments, the splitting ratio of the beam splitter prism is at least one of 90:10, 80:20, 70:30, 60:40, and 50:50.

[0019] In some embodiments, the dark field imaging component includes a dark field camera, which is used to receive scattered light generated by the object under test based on the dark field light source and reflected by the transmission component, and to capture a dark field image based on the scattered light.

[0020] Through an optical detection system as provided above, the embodiment of the present application realizes an optical detection system 100 that can be used for bright field illumination and dark field illumination by adopting a common transmission component 103, which not only simplifies the design of the optical detection system and reduces costs, but also improves the compatibility and performance of optical detection, thereby adapting to a variety of optical detection application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other objects, features and advantages of the exemplary embodiments of the present application will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0022] Figure 1 A schematic diagram showing an optical detection system according to some embodiments of the present application;

[0023] Figure 2 A schematic structural diagram of a collimating lens assembly according to some embodiments of the present application is shown;

[0024] Figure 3 A diagram showing the spot diameter of a collimating lens assembly according to some embodiments of the present application;

[0025] Figure 4 A schematic structural diagram of a collimating lens assembly according to some embodiments of the present application is shown;

[0026] Figure 5 A diagram showing the spot diameter of a collimating lens assembly according to some embodiments of the present application;

[0027] Figure 6 A schematic structural diagram of a tube lens assembly in some embodiments of the present application is shown;

[0028] Figure 7 A diagram showing the spot diameter of a tube lens assembly according to some embodiments of the present application;

[0029] Figure 8 A diagram showing field curvature and distortion of a tube lens assembly according to some embodiments of the present application;

[0030] Figure 9 A schematic structural diagram of a tube lens assembly in some embodiments of the present application is shown;

[0031] Figure 10 A diagram showing the spot diameter of a tube lens assembly according to some embodiments of the present application;

[0032] Figure 11 Graphs showing field curvature and distortion of the tube lens assembly of some embodiments of the present application. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0034] It should be understood that the terms "include" and "comprising" used in the description and claims of this application indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0035] It should also be understood that the terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this specification and claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" as used in this specification and claims refers to any and all possible combinations of one or more of the associated listed items, including and including these combinations.

[0036] As used in this specification and claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0037] The specific implementation of the present application will be described in detail below with reference to the accompanying drawings.

[0038] Reference Figure 1 , Figure 1 Schematic diagram of an optical detection system 100 according to some embodiments of the present application is shown. Figure 1 As shown, an embodiment of the present application proposes an optical detection system 100, which at least includes a bright field lighting component 101, a dark field lighting component 102, a transmission component 103, a bright field imaging component 104 and a dark field imaging component 105. Among them, the bright field lighting component 101 is used to transmit a bright field light source to the transmission component 103. The transmission component 103 can be used to reflect the bright field light source emitted by the bright field lighting component 101 to the object to be measured 106, and reflect the reflected light generated by the object to be measured 106 based on the bright field light source back to the bright field imaging component 104. The bright field imaging component 104 is used to receive the reflected light generated by the object to be measured 106 based on the bright field light source reflected by the transmission component 103, and to collect a bright field image based on the reflected light. According to such a setting, the bright field lighting component 101, the transmission component 103 and the bright field imaging component 104 of the embodiment of the present application constitute a bright field lighting optical detection optical path, which can be used for bright field lighting optical detection.

[0039] Furthermore, the dark-field illumination component 102 is used to emit a dark-field light source to the object under test 106. The transmission component 103 can also be used to reflect the scattered light generated by the object under test 106 based on the dark-field light source back to the dark-field imaging component 105. The dark-field imaging component 105 is used to receive the scattered light generated by the object under test 106 based on the dark-field light source reflected by the transmission component 103, and to capture a dark-field image based on the scattered light. Through the above arrangement, the dark-field illumination component 102, the transmission component 103, and the dark-field imaging component 105 of the embodiment of the present application constitute a dark-field illumination optical detection optical path, which can be used for dark-field illumination optical detection.

[0040] Based on the above description, it can be seen that the brightfield illumination assembly 101, transmission assembly 103, and brightfield imaging assembly 104 of the embodiments of the present application can be used for brightfield illumination optical inspection; and the darkfield illumination assembly 102, transmission assembly 103, and darkfield imaging assembly 105 can be used for darkfield illumination optical inspection. Therefore, the optical inspection system of the embodiments of the present application can simultaneously perform brightfield illumination optical inspection and darkfield illumination optical inspection. This not only improves the performance of optical inspection, but also achieves the purpose of improving the compatibility and performance of optical inspection, thereby simultaneously adapting to different optical inspection application scenarios.

[0041] Furthermore, based on the above description, it can be seen that the bright field illumination optical detection and the dark field illumination optical detection of the embodiment of the present application share the transmission component 103. With such a configuration, the optical detection system of the embodiment of the present application can also simplify the design and reduce the cost.

[0042] Combination of the above Figure 1 The optical detection system 100 of the present application is described in general. The embodiment of the present application realizes an optical detection system 100 that can be used for bright field illumination and dark field illumination by adopting a common transmission component 103. This not only simplifies the design of the optical detection system and reduces costs, but also improves the compatibility and performance of optical detection, thereby adapting to a variety of optical detection application scenarios.

[0043] It is understood that the optical inspection system 100 of the embodiment of the present application can be used for both brightfield and darkfield optical inspection. Therefore, the optical inspection system 100 of the embodiment of the present application can not only clearly present surface features in high-contrast scenarios, making it particularly suitable for detecting and identifying edges, textures, and pattern features, but can also effectively highlight tiny surface structures or defects in low-contrast environments. This system significantly improves the performance of defect detection in the semiconductor industry, reduces costs, and enhances adaptability, enabling it to better address a variety of complex inspection needs.

[0044] However, it should be understood by those skilled in the art that Figure 1The optical detection system 100 shown is exemplary and non-limiting, and those skilled in the art can make adjustments as needed. Next, multiple embodiments and variations of the optical detection system 100 of some embodiments of the present application are further described.

[0045] In some embodiments, as Figure 1 As shown, the brightfield illumination assembly 101 may include a brightfield light source assembly 1010, a first optical fiber 1011, a first light homogenizing rod 1012, a collimating lens assembly 1013, and a reflector 1014, which are arranged in sequence. The brightfield light emitted by the brightfield light source assembly 1010 passes through the first optical fiber 1011, the first light homogenizing rod 1012, the collimating lens assembly 1013, and the reflector 1014 in sequence before being reflected to the transmission assembly 103. This arrangement ensures that the brightfield light ultimately reflected to the transmission assembly 103 has good quality.

[0046] In some embodiments, the bright field light source component 1010 can be a component such as an LED that can be used to emit bright field light sources. The embodiments of the present application do not specifically limit this. Those skilled in the art can flexibly select the corresponding component as the bright field light source component 1010 according to actual needs.

[0047] In some embodiments, one end of the first optical fiber 1011 is connected to the bright field light source assembly 1010, and the other end is connected to the first homogenizing rod 1012 to transmit the bright field light source emitted by the bright field light source assembly 1010 to the first homogenizing rod 1012. The first homogenizing rod 1012 is used to convert the received bright field light source into uniform light. The collimating lens group 1013 is used to collimate the uniform bright field light source. The reflector 1014 is used to reflect the collimated bright field light source to the transmission assembly 103. The bright field light source emitted by the bright field light source assembly 1010 is thus transmitted through the first optical fiber 1011, homogenized by the first homogenizing rod 1012, collimated by the collimating lens group 1013, and reflected by the reflector 1014 before being transmitted to the transmission assembly 103.

[0048] Combination of the above Figure 1 In general, the bright field illumination component 101 in the optical detection system 100 of the present application is further described. The embodiment of the present application is configured with a bright field illumination component 101 including a bright field light source component 1010, a first optical fiber 1011, a first homogenizing rod 1012, a collimating lens group 1013 and a reflector 1014, so that the bright field light source emitted by the bright field light source component 1010 is sequentially transmitted through the first optical fiber 1011, homogenized by the first homogenizing rod 1012, collimated by the collimating lens group 1013 and reflected by the reflector 1014, and then transmitted to the transmission component 103, so that the bright field light source finally reflected to the transmission component 103 has better quality.

[0049] However, it should be understood by those skilled in the art that Figure 1 The illustrated optical inspection system 100 is illustrative and non-restrictive, and those skilled in the art may modify it as needed. For example, the parameters of the components of the brightfield illumination assembly 101 may be adjusted based on actual inspection requirements. The following further describes various embodiments and variations of the optical inspection system 100 according to some embodiments of the present application.

[0050] In some embodiments, the focal length range of the collimator lens assembly 1013 described above can be [40, 100] mm to accommodate different illumination NAs (numerical apertures). The arrangement and type of the lenses within the collimator lens assembly 1013 are not specifically limited in this embodiment. Those skilled in the art can configure them according to actual needs to improve the light spot imaging quality of the collimator lens assembly 1013.

[0051] In some embodiments, the surface of the reflector 1014 may be coated with a protective silver reflective film layer to improve the reflectivity of the reflector 1014 .

[0052] It is understandable that the above-mentioned parameters of each component can be used to further improve the overall performance of the bright field illumination component 101, so that the bright field light source ultimately reflected therefrom has better quality.

[0053] Next, Example 1 and Example 2 are further described to verify the performance of the bright field illumination assembly 101 of some embodiments of the present application.

[0054] Example 1:

[0055] The light output size of the first optical fiber 1011 is 9mm*1.5mm, with an NA of 0.25. The 9mm in the light output size represents the width of the light beam, and the 1.5mm represents the height of the light beam. The dimensions of the first homogenizer 1012 are 9mm*1.5mm*30mm, corresponding to the length, width, and height of the first homogenizer 1012, respectively. The spectral range of the brightfield light source assembly 1010, the first optical fiber 1011, and the first homogenizer is set to the spectral range of visible light, that is, the wavelength is [400, 700]nm. The focal length of the collimator lens assembly 1013 is 45mm. The surface of the reflector 1014 is coated with a protective silver reflective film.

[0056] Further, refer to Figure 2 , Figure 2 Schematic diagram of the structure of the collimating lens assembly of some embodiments of the present application is shown. Figure 2 As shown, the collimator lens group 1013 is composed of 9 lenses. Specifically, the collimator lens group 1013 is arranged along the optical axis from the object side to the image side (corresponding to Figure 2The collimating lens assembly 1013 may be composed of, from left to right, a biconvex lens, a convex lens, a convex lens, a convex lens, a plano-convex lens, a plano-concave lens, a biconcave lens, a concave lens, and a concave lens, in sequence. The object side refers to the side close to the object plane of the collimating lens, and the image side refers to the side close to the image plane of the collimating lens. In addition, the object plane of the collimating lens assembly 1013 may be a plane lens, and the image plane may be a convex lens. It is understood that the object plane of the collimating lens assembly 1013 refers to the place where light enters or the optical surface at the front end of the collimating lens assembly. The image plane of the collimating lens assembly 1013 refers to the plane where light is finally focused or forms an image after being refracted or reflected by the nine lenses in the collimating lens assembly 1013.

[0057] Correspondingly, the detailed parameters of the above lenses and the object plane and image plane in the collimator lens group 1013 can be referred to in the following Table 1. It should be noted that the parameters of sequence numbers 1 and 2 in Table 1 are the parameters of the object side and image side of the object plane of the collimator lens group 1013, respectively. The parameters of sequence numbers 21 and 22 are the parameters of the object side and image side of the image plane of the collimator lens group 1013, respectively. In addition, the parameters of sequence numbers 3 to 20 in the table are in ascending order, and the parameters of each adjacent two sequence numbers correspond to the parameters of the object side and image side of each lens set in sequence from the object side to the image side. For example, the parameters of sequence numbers 3 and 4 are the parameters of the object side and image side of the first biconvex lens set, respectively; the parameters of sequence numbers 5 and 6 are the parameters of the object side and image side of the second convex lens set, respectively.

[0058] Table 1. Detailed parameters of the collimator lens assembly

[0059]

[0060] Reference Figure 3 , Figure 3 The following diagram shows the spot diameter of the collimating lens assembly in some embodiments of the present application. Figure 10 The left column shows the field of view position and the deviation of the image plane at that field of view position. The field of view position refers to the angle or position where the light enters the collimator lens group. For example Figure 3 The first row of the left column shows (0.00, 1.00) and (0.000, 4.559), where (0.00, 1.00) is the field of view position and (0.000, 4.559) is the deviation of the image plane at the (0.00, 1.00) field of view position. The RMS=a shown in the right column indicates that the specific value of the root mean square of the spot diameter is a, and 100%=b indicates that the specific value of the maximum spot diameter is b. The relevant parameters in the spot diameter diagrams given in Examples 2 to 4 below are explained in the same way as Figure 3 Same, no further details will be given. Figure 3 It can be seen that the imaging spot diameter of the collimating lens group 1013 has a root mean square (RMS) of less than 5.4 μm across the entire field of view, indicating good imaging quality.

[0061] Example 2:

[0062] The light output size of the first optical fiber 1011 is 8mm*1.7mm, and NA=0.25. 8mm corresponds to the width of the light beam, and 1.7mm corresponds to the height of the light beam. The size of the first homogenizer 1012 is 7mm*1.7mm*30mm, which correspond to the length, width, and height of the first homogenizer 1012, respectively. The focal length of the collimator lens group 1013 is 95mm. The surface of the reflector 1014 is coated with a protective silver reflective film. Similar to Example 1, the spectral range of the bright field light source assembly 1010, the first optical fiber 1011, and the first homogenizer are all equal to the spectral range of visible light, that is, the wavelength is [400, 700]nm.

[0063] Reference Figure 4 , Figure 4 Schematic diagram of the structure of the collimating lens assembly of some embodiments of the present application is shown. Figure 4 As shown, collimator lens assembly 1013 also consists of nine lenses, but its structure differs from that of the collimator lens assembly in Example 1. Specifically, collimator lens assembly 1013 may be composed of, in order from the object side to the image side, a biconvex lens, a convex lens, a biconvex lens, a convex lens, a convex lens, a planar lens, a concave lens, a biconvex lens, and a concave lens. Furthermore, the object plane of collimator lens assembly 1013 may be a planar lens, and the image plane may be a plano-convex lens.

[0064] Furthermore, the various lenses, object plane, and image plane of the collimating lens group 1013 of this example adopt detailed parameters that are different from those of Example 1, and specific reference may be made to the following Table 2. It should be noted that the parameters of sequence numbers 1 and 2 in Table 2 are the parameters of the object side and image side of the object plane of the collimating lens group 1013, respectively. The parameters of sequence numbers 22 and 23 are the parameters of the object side and image side of the image plane of the collimating lens group 1013, respectively. In addition, the parameters of sequence numbers 3 to 21 in the table, in ascending order, the parameters of two adjacent sequence numbers correspond to the parameters of each lens set in sequence from the object side to the image side. For example, the parameters of sequence numbers 3 and 4 are the parameters of the object side and image side of the first set biconvex lens, respectively; the parameters of sequence numbers 5 and 6 are the parameters of the object side and image side of the second set convex lens, respectively.

[0065] Table 2. Detailed parameters of the collimator lens assembly

[0066]

[0067] Reference Figure 5 , Figure 5 The following diagram shows the spot diameter of the collimating lens assembly in some embodiments of the present application. Figure 5 It can be seen that the imaging spot diameter of the collimating lens group 1013 is less than 7.2um in the whole field of view RMS, which has good imaging quality.

[0068] It is understood that those skilled in the art can adjust the parameters of each component in the brightfield illumination assembly 101 based on the content and teachings disclosed in this embodiment, and do not necessarily have to be consistent with the parameters used in the example proposed in this embodiment. The following further describes multiple embodiments and variations of the optical detection system 100 of some embodiments of the present application.

[0069] In some embodiments, as Figure 1 As shown, the darkfield illumination assembly 102 may include a darkfield light source assembly 1020, a second optical fiber 1021, a second homogenizing rod 1022, and a relay lens assembly 1023, which are arranged in sequence. The darkfield light emitted by the darkfield light source assembly 1020 passes through the second optical fiber 1021, the second homogenizing rod 1022, and the relay lens assembly 1023 in sequence before being reflected toward the object under test 106. This arrangement ensures that the darkfield light ultimately reflected toward the object under test 106 has good quality.

[0070] In some embodiments, the dark field light source component 1020 may be any component that can be used to emit a dark field light source. For example, the dark field light source component 1020 may be a laser, an LED, or other component, which is not specifically limited in this embodiment.

[0071] In some embodiments, one end of the second optical fiber 1021 is connected to the dark field light source assembly 1020, and the other end is connected to the second homogenizing rod 1022 to transmit the dark field light source emitted by the dark field light source assembly 1020 to the second homogenizing rod 1022. Similar to the function of the first homogenizing rod 1012 described above, the second homogenizing rod 1022 of this embodiment is used to convert the received dark field light source into uniform light. The relay lens assembly 1023 is used to focus the uniform dark field light source onto the object to be measured 106. The dark field light source emitted by the dark field light source assembly 1020 is sequentially transmitted through the second optical fiber 1021, homogenized by the second homogenizing rod 1022, and focused by the relay lens assembly 1023 before being transmitted to the object to be measured 106. After being irradiated by the dark field light source, the object to be measured 106 will generate scattered light.

[0072] Combination of the above Figure 1 The darkfield illumination assembly 102 in the optical inspection system 100 of the present application has been further generally described. In the embodiment of the present application, the darkfield illumination assembly 102 is configured to include a darkfield light source assembly 1020, a second optical fiber 1021, a second homogenizing rod 1022, and a relay lens assembly 1023. The darkfield light emitted by the darkfield light source assembly 1020 is sequentially transmitted through the second optical fiber 1021, homogenized by the second homogenizing rod 1022, and focused by the relay lens assembly 1023 before being transmitted to the object under test 106. This configuration ensures that the darkfield light ultimately reflected to the object under test 106 has good quality.

[0073] However, it should be understood by those skilled in the art that Figure 1 The optical inspection system 100 shown is exemplary and non-restrictive, and those skilled in the art may modify it as needed. For example, the parameters of each component in the darkfield illumination assembly 102 may be set based on actual inspection requirements. The following further describes various embodiments and variations of the optical inspection system 100 according to some embodiments of the present application.

[0074] In some embodiments, as Figure 1 As shown, the transmission component 103 may include a microscope objective lens 1030, a dichroic mirror 1031, a beam splitter 1032, a tube lens assembly 1033 and a double-sided reflector 1034, which are arranged in sequence starting from a position close to one end of the object to be measured 106.

[0075] As can be seen from the foregoing description, the transmission component 103 is used to reflect the brightfield light source emitted by the brightfield illumination component 101 toward the object under test 106, and to reflect the reflected light generated by the brightfield light source from the object under test 106 back to the brightfield imaging component 104. Furthermore, the transmission component 103 is used to reflect the scattered light generated by the darkfield light source from the object under test 106 back to the darkfield imaging component 105.

[0076] Specifically, if Figure 1 As shown in the transmission path of the brightfield light source, the brightfield light emitted by the brightfield illumination assembly 101 is sequentially split by the beam splitter 1032, reflected by the dichroic mirror 1031, and focused by the microscope objective 1030 before being reflected toward the object under test 106. The reflected light generated by the object under test 106 based on the brightfield light source is sequentially collimated by the microscope objective 1030, transmitted by the dichroic mirror 1031, split by the beam splitter 1032, focused by the tube lens assembly 1033, and reflected from the left side by the double-sided reflector 1034 before being reflected back to the brightfield imaging assembly 104. This allows the brightfield imaging assembly 104 to capture a brightfield image based on the reflected light, thereby achieving optical inspection using brightfield illumination. Similarly, the scattered light generated by the object to be measured 106 based on the dark field light source will also be reflected back to the dark field imaging component 105 after being collimated by the microscope objective 1030, transmitted by the dichroic mirror 1031, split by the beam splitter 1032, focused by the tube lens group 1033, and reflected by the right side of the double-sided reflector 1034, so that the dark field imaging component 105 can collect dark field images based on the scattered light, thereby realizing optical detection of dark field illumination.

[0077] Further based on Figure 1It can be seen that although the reflected light of the object under test based on the bright field light source and the scattered light generated based on the dark field light source share the transmission component 103, their transmission light paths in the transmission component are different. This allows the reflected light generated by the object under test 106 based on the bright field light source in the embodiment of the present application to be ultimately reflected by the left side of the double-sided reflector 1034 to the bright field imaging component 104, while the scattered light generated by the object under test based on the dark field light source is ultimately reflected by the right side of the double-sided reflector 1034 to the dark field imaging component 105 without interfering with each other.

[0078] Such a setting can effectively prevent the reflected light generated by the object under test based on the bright field light source from being mistakenly reflected to the dark field imaging component 105, while the scattered light generated by the object under test based on the dark field light source is mistakenly reflected to the bright field imaging component 104, thereby enabling the optical detection system of the embodiment of the present application to be used for optical detection of bright field illumination and dark field illumination at the same time.

[0079] In some embodiments, the focal length range of the lens assembly 1033 can be set to [180, 450] mm, so that the focal length of the lens assembly 1033 can be adjusted as needed to obtain different imaging magnifications. The arrangement and type of the lenses within the lens assembly 1033 are not specifically limited in this embodiment, and those skilled in the art can adjust them according to actual needs to improve imaging quality.

[0080] In some embodiments, the surface of the double-sided reflective mirror 1034 may be coated with a protective silver reflective film layer to improve the reflectivity of the double-sided reflective mirror 1034 .

[0081] In some embodiments, as Figure 1 As shown, the transmission component 103 may further include an autofocus sensor 1035. The autofocus sensor 1035 is located at the same horizontal line as the dichroic mirror 1031, and is configured to receive light reflected by the microscope objective lens 1030 and adjust the focus of the microscope objective lens 1030 based on the light, thereby ensuring that the microscope objective lens 1030 has good imaging quality.

[0082] Next, Example 3 and Example 4 are further described to verify the performance of the transmission component 103 of some embodiments of the present application.

[0083] Example 3:

[0084] The parameters of each component in the brightfield illumination assembly 101 are the same as those in Example 1. The darkfield light source assembly 1020, second optical fiber 1021, and second homogenizing rod 1022 in the darkfield illumination assembly 102 can utilize the same components and parameters as the brightfield light source assembly 1010, first optical fiber 1011, and first homogenizing rod 1012 in the brightfield illumination assembly 101, respectively, to improve the imaging quality of the darkfield illumination assembly. The magnification of the relay lens assembly 1023 is 1X. It is understood that 1X means 1x.

[0085] The microscope objective 1030 in the transmission assembly 103 supports a magnification of 1.5-50 times. The dichroic mirror 1031 reflects light with a wavelength of 785 nm and transmits light with a wavelength of 400 to 700 nm. The beam splitter 1032 has a 50:50 splitting ratio, which represents the energy distribution ratio when the beam splitter divides the incident light into reflected light and transmitted light. The entrance pupil diameter of the tube lens assembly 1033 is greater than 25 mm, and the focal length is 185 mm. The double-sided reflector 1034 is coated with a protective silver reflective film. The autofocus sensor 1035 uses light with a wavelength of 785 nm to focus the microscope objective 1030.

[0086] Further, refer to Figure 6 , Figure 6 Schematic diagram of the structure of the tube lens assembly of some embodiments of the present application is shown. Figure 6 As shown, the barrel lens group 1033 is composed of 5 lenses. Specifically, the barrel lens group 1033 can be composed of a biconvex lens, a single convex lens, a biconvex lens, a concave lens, and a concave lens in sequence from the object side to the image side along the optical axis. The detailed parameters of this barrel lens group 1033 can be referred to in the following Table 3. In Table 3, sequence numbers 1 and 2 correspond to the parameters of the object side and image side of the object surface of the barrel lens group 1033. Sequence numbers 3 to 12 are in ascending order, and the parameters of each adjacent two sequence numbers correspond to the parameters of the object side and image side of each lens set in sequence from the object side to the image side. For example, sequence numbers 3 and 4 are respectively the parameters of the object side and image side of the first biconvex lens set, and sequence numbers 5 and 6 are respectively the parameters of the object side and image side of the second single convex lens set, wherein the "---" in sequence number 6 indicates that there are no parameters on the image side in this single convex lens.

[0087] Table 3. Detailed parameters of the tube lens assembly

[0088] surface Curvature radius (mm) Thickness (mm) Material 1 infinity 350 2 infinity 3 245.116735361758 15 HZF62_CDGM 4 -638.1912151 19.9860685915883 5 -225.1173402 15 HZF52A_CDGM 6 --- --- 7 132.454999044192 25.888757304058 HZPK7_CDGM 8 -123.6330096 8.63123337400356 9 -76.35147047 13.2310001623508 HZF88_CDGM 10 -80.76586654 57.730914615225 11 -73 10.0217144725673 HZLAF69A_CDGM 12 -74.41187502 266.292821471566

[0089] Reference Figure 7 , Figure 7 The spot diameter diagram of the tube lens assembly in some embodiments of the present application is shown. Figure 7 It can be seen that the imaging spot diameter of the tube lens group 1033 has an RMS of less than 11um in the entire field of view, which is close to the diffraction limit and has good imaging quality. It can be further known that the field curvature diagram shows the deviation between the image plane and the ideal plane by plotting the distance between the image point at different field of view positions and the ideal image plane. The depth of focus indicates the allowable deviation range for the image plane to maintain clear imaging. If the field curvature can be controlled within the depth of focus, it means that the imaging quality is good. The distortion diagram reflects the degree of distortion between the actual image point position and the ideal image point position by plotting the deviation between the actual image point position and the ideal image point position. The quality of the imaging can be clearly seen through the field curvature diagram and the distortion diagram. Therefore, refer to Figure 8 , Figure 8The field curvature and distortion diagrams of the tube lens assembly of some embodiments of the present application are shown. Figure 8 The left image is a field curvature diagram, where the horizontal axis represents the field of view position and the vertical axis represents the deviation between the image plane and the ideal plane. The right image is a distortion diagram, where the horizontal axis represents the field of view position and the vertical axis represents the deviation between the actual image point position and the ideal image point position, i.e., the amount of distortion. The explanation of the relevant parameters in the field curvature diagram and distortion diagram given in Example 4 below is similar to Figure 8 Same, no further details will be given. Figure 8 It can be seen that the field curvature of the tube lens assembly is well controlled within the focal depth range, and the distortion is less than 0.5%. This shows that the tube lens assembly has good imaging quality, thereby achieving the purpose of improving the performance of the optical inspection system.

[0090] Example 4:

[0091] The parameters of each component in the brightfield illumination assembly 101 and the darkfield illumination assembly 102 are the same as those in the aforementioned Example 3. The entrance pupil diameter of the tube lens assembly 1033 in the transmission assembly 103 is greater than 25 mm, and the focal length is 415 mm. The remaining component parameters of the transmission assembly 103 are the same as those in the aforementioned Example 3.

[0092] Further, refer to Figure 9 , Figure 9 Schematic diagram of the structure of the tube lens assembly of some embodiments of the present application is shown. Figure 9 As shown, the barrel lens assembly 1033 of this example is composed of 5 lenses, but adopts a different structure from the above-mentioned Example 3. Specifically, the barrel lens assembly 1033 is composed of a biconvex lens, a biconcave lens, a biconvex lens, a concave lens, and a concave lens in sequence from the object side to the image side along the optical axis. In addition, the detailed parameters of the barrel lens assembly of this example are also different from those of the above-mentioned Example 3. The detailed parameters of the barrel lens assembly 1033 of this example can be referred to in the following Table 4. In Table 4, sequence numbers 1 and 2 are respectively the parameters of the object side and image side corresponding to the object surface of the barrel lens assembly 1033. Sequence numbers 3 to 12 are in ascending order, and the parameters of each adjacent two sequence numbers correspond to the parameters of the object side and image side of each lens set in sequence from the object side to the image side. For example, sequence numbers 2 and 3 are respectively the parameters of the object side and image side of the first biconvex lens set, and sequence numbers 4 and 5 are respectively the parameters of the object side and image side of the second biconcave lens set.

[0093] Table 4. Detailed parameters of the tube lens assembly

[0094] surface Curvature radius (mm) Thickness (mm) Material 1 infinity 410 2 infinity 3 214.114322820755 15 HZF62_CDGM 4 -2629.244632 23.1789638966225 5 -240.8034589 15 HZPK7_CDGM 6 90.8869926763509 5.28614981257154 7 127.663826674611 18.7898888705512 HZPK7_CDGM 8 -131.6677331 6.17070326600604 9 -74.82278543 11.0426324032926 HZF62_CDGM 10 -74.90061369 47.2982967179375 11 -64.90805015 13.4811134463867 HZLAF69A_CDGM 12 -68.21650867 362.479973372699

[0095] Reference Figure 10 , Figure 10 The spot diameter diagram of the tube lens assembly in some embodiments of the present application is shown. Figure 10 It can be seen that the imaging spot diameter of the 1033 tube lens group is less than 5um in the whole field of view RMS, which is close to the diffraction limit and has good imaging quality. Figure 11 , Figure 11 The field curvature and distortion diagrams of the tube lens assembly of some embodiments of the present application are shown. Figure 11 The left image in the middle is the field curvature image, and the right image is the distortion image. Figure 11 It can be seen that the field curvature of the tube lens assembly is well controlled within the focal depth range, and the distortion is less than 0.5%. Based on the above, it can be seen that the tube lens assembly of this embodiment has good imaging quality and can achieve the effect of improving the performance of the optical detection system.

[0096] Combination of the above Figure 1 The transmission component 103 in the optical detection system 100 of the present application is further described in general. The embodiment of the present application is provided with a microscope objective 1030, a dichroic mirror 1031, a beam splitter 1032, a tube lens group 1033 and a double-sided reflector 1034, so that the bright field light source emitted by the bright field illumination component 101 passes through the beam splitter 1032, the dichroic mirror 1031 and the microscope objective 1030 in sequence and is reflected to the object to be measured 106; and the object to be measured 106 generates a reflection light based on the bright field light source and the reflected light. The scattered light generated by the dark-field light source of the object to be measured passes through the microscope objective 1030, the dichroic mirror 1031, the beam splitter 1032, the tube lens group 1033 and the double-sided reflector 1034 in sequence, and is reflected back to the bright-field imaging component 104 and the dark-field imaging component 105 respectively, so that the bright-field imaging component 104 can collect bright-field images and the dark-field imaging component can collect dark-field images, thereby realizing optical detection of bright-field illumination and dark-field illumination, achieving the purpose of improving the compatibility of optical detection, and thus adapting to various application scenarios of optical detection.

[0097] However, it should be understood by those skilled in the art that Figure 1 The optical detection system 100 shown is exemplary and non-limiting, and those skilled in the art can make adjustments as needed. Next, multiple embodiments and variations of the optical detection system 100 of some embodiments of the present application are further described.

[0098] In some embodiments, as Figure 1 As shown, the bright field imaging component 104 includes a bright field camera 1040, which is used to receive the reflected light generated by the bright field light source of the object under test 106 reflected by the transmission component 103, and to collect a bright field image based on the reflected light.

[0099] In some embodiments, the dark field imaging component 105 may be a dark field camera, which is used to receive scattered light generated by the object under test 106 based on a dark field light source and reflected by the transmission component 103, and to capture a dark field image based on the scattered light.

[0100] As an example, in some embodiments, the lens diameters of the brightfield camera 1040 and the darkfield camera 105 may be greater than 60 mm.

[0101] Combination of the above Figure 1 The bright field imaging component 104 and the dark field imaging component 105 in the optical detection system 100 of the present application are generally described. However, it should be understood by those skilled in the art that Figure 1 The optical detection system 100 shown is exemplary and non-limiting, and those skilled in the art can make adjustments as needed. Next, multiple embodiments and variations of the optical detection system 100 of some embodiments of the present application are further described.

[0102] In some embodiments, as Figure 1 As shown, the brightfield imaging component 104 also includes a re-inspection camera 1041, which is used to receive the reflected light generated by the brightfield light source from the object under test 106 reflected by the transmission component 103, and to capture a re-inspection image based on the reflected light. To enable the re-inspection camera to capture the re-inspection image, the transmission component 103 of the embodiment of the present application also includes a beam splitter prism 1036 disposed between the brightfield camera 1040 and the double-sided reflector 1034. The beam splitter prism 1036 is used to reflect the reflected light generated by the brightfield light source from the object under test reflected by the double-sided reflector 1034 to the re-inspection camera, so that the accessory camera can perform a re-inspection based on the reflected light, thereby improving the accuracy of optical inspection.

[0103] Specifically, the beam splitter prism 1036 decomposes the reflected light of the object 106 under test, which is reflected by the double-sided reflector 1034 and generated based on the brightfield light source, into a first beam of light and a second beam of light, so as to reflect the first beam of light to the brightfield camera 1040 and the second beam of light to the re-inspection camera 1041. This causes the brightfield camera 1040 to capture a brightfield image based on the first beam of light, and the re-inspection camera 1041 to capture a re-inspection image based on the second beam of light. It can be seen from this that the re-inspection optical path of the embodiment of the present application is the same as the brightfield illumination optical path, thereby simplifying the design of the optical inspection system, reducing costs, and improving the performance of the optical inspection system, and further improving the compatibility of the optical inspection, thereby adapting to a variety of optical inspection application scenarios.

[0104] As an example, in some embodiments, the splitting ratio of the incident light by the beam splitter 1036 can be set to at least one of 90:10, 80:20, 70:30, 60:40, and 50:50 to suit different application scenarios. It is understood that the splitting ratio represents the energy distribution ratio of the incident light into the first beam and the second beam.

[0105] Combination of the above Figure 1In general, the optical inspection system 100 of the present application is further described. The embodiment of the present application realizes re-inspection detection based on bright field illumination optical inspection by adding a re-inspection camera 1041 and adding a dichroic prism 1036 between the bright field camera 1040 and the double-sided reflector 1034. Therefore, the optical inspection system of the embodiment of the present application can simultaneously realize bright field illumination optical inspection, re-inspection detection based on bright field illumination optical inspection and dark field illumination optical inspection, thereby further improving the compatibility of optical inspection to adapt to various optical inspection application scenarios.

[0106] However, it should be understood by those skilled in the art that Figure 1 The optical inspection system 100 shown is exemplary and non-limiting, and those skilled in the art may modify it as needed. For example, in some embodiments, the optical inspection system 100 may further include a processing component for performing defect detection on the object 106 based on the brightfield image captured by the brightfield imaging component 104 and / or the darkfield image captured by the darkfield imaging component 105.

[0107] Although multiple embodiments of the present application have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art can conceive of many changes, modifications, and alternatives without departing from the thought and spirit of the present application. It should be understood that in the process of practicing the present application, various alternatives to the embodiments of the present application described herein can be adopted. The accompanying claims are intended to define the scope of protection of the present application and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. An optical detection system, characterized in that: include: a bright field illumination component for emitting a bright field light source to the transmission component; A dark field illumination component, which is used to emit a dark field light source to the object under test; Transmission components, including microscope objective, dichroic mirror, beam splitter, tube lens assembly and double-sided mirror; It is used to reflect the bright field light source emitted by the bright field illumination assembly to the object under test after passing through the beam splitter, the dichroic mirror, and the microscope objective lens in sequence; and is used to reflect the reflected light generated by the object under test based on the bright field light source and the scattered light generated by the object under test based on the dark field light source back to the bright field imaging assembly and the dark field imaging assembly respectively after passing through the microscope objective lens, the dichroic mirror, the beam splitter, the tube lens group, and the double-sided reflector in sequence, wherein the transmission optical paths of the reflected light generated by the object under test based on the bright field light source and the scattered light generated by the dark field light source are different; a bright field imaging component, configured to receive the reflected light generated by the bright field light source and reflected by the transmission component from the object under test, and to capture a bright field image based on the reflected light; as well as A dark field imaging component is used to receive the scattered light generated by the object under test based on the dark field light source and reflected by the transmission component, and to collect a dark field image based on the scattered light.

2. The optical detection system according to claim 1, characterized in that The bright field illumination assembly includes a bright field light source assembly, a first optical fiber, a first light homogenizing rod, a collimating lens group, and a reflector; wherein, The bright field light source emitted by the bright field light source assembly passes through the first optical fiber, the first light homogenizing rod, the collimating lens group and the reflector in sequence and is then reflected to the transmission assembly.

3. The optical detection system according to claim 2, characterized in that: The focal length range of the collimating lens group is [40, 100] mm.

4. The optical detection system according to claim 2, characterized in that: The reflector is plated with a protective silver reflective film layer.

5. The optical detection system according to claim 1, characterized in that: The dark field illumination assembly includes a dark field light source assembly, a second optical fiber, a second light homogenizing rod, and a relay lens assembly; wherein, The dark field light source emitted by the dark field light source assembly passes through the second optical fiber, the second light homogenizing rod and the relay lens group in sequence and is reflected to the object to be measured.

6. The optical detection system according to claim 1, characterized in that: The transmission component also includes an autofocus sensor; wherein, The autofocus sensor and the dichroic mirror are on the same horizontal line, so as to receive the light reflected by the microscope objective lens and adjust the focus according to the light.

7. The optical detection system according to claim 1, characterized in that: The focal length range of the tube lens group is [180, 450] mm.

8. The optical detection system according to claim 1, wherein: The double-sided reflector is plated with a protective silver reflective film layer.

9. The optical detection system according to claim 1, characterized in that: The bright field imaging component includes a bright field camera, which is used to receive the reflected light of the measured object generated based on the bright field light source and reflected by the transmission component, and to collect a bright field image based on the reflected light.

10. The optical detection system according to claim 1, wherein: The bright field imaging component also includes a re-inspection camera, which is used to receive the reflected light generated by the object to be measured based on the bright field light source reflected by the transmission component, and to collect a re-inspection image based on the reflected light; the transmission component also includes a dichroic prism, which is used to reflect the reflected light generated by the object to be measured based on the bright field light source reflected by the double-sided reflector to the re-inspection camera.

11. The optical detection system according to claim 10, characterized in that: The splitting ratio of the beam splitter prism is at least one of 90:10, 80:20, 70:30, 60:40, and 50:

50.

12. The optical detection system according to claim 1, wherein: The dark field imaging component includes a dark field camera, which is used to receive the scattered light generated by the object under test based on the dark field light source and reflected by the transmission component, and to collect a dark field image based on the scattered light.

Images