A fluorescence detection imaging system and a fluorescence detection apparatus

Abstract

The application discloses a fluorescent detection imaging system and a fluorescent detection equipment, and relates to the technical field of visual detection equipment.The fluorescent detection imaging system comprises a bright field optical fiber, a high-transmittance ultraviolet lens group, a Kohler lens group, a dichroic mirror, a half-reflection half-transmission lens, an objective lens, a filter, an imaging lens group and a main camera; when the application is used, ultraviolet light is introduced by the bright field optical fiber, sequentially passes through the high-transmittance ultraviolet lens group and the Kohler lens group, is reflected by the dichroic mirror into the half-reflection half-transmission lens, is reflected into the objective lens through the half-reflection half-transmission lens, and is then irradiated on a measured object; the excited fluorescence of the measured object passes through the objective lens and the half-reflection half-transmission lens, enters the filter, the filter completely filters out the excited ultraviolet light band, and then the imaging lens group is used to image on the main camera; thereby, the fluorescent detection of the measured object is realized, and the detection of the electrically active defects, such as the lattice dislocation, metal impurity pollution, hidden crack and uneven diffusion, in the measured object is realized.

Description

Technical Field

[0001] This invention relates to the field of visual inspection equipment technology, specifically to a fluorescence detection imaging system and fluorescence detection equipment. Background Technology

[0002] A wafer is the fundamental material for manufacturing semiconductor chips. It is typically made from high-purity single-crystal silicon through processes such as dicing, grinding, and polishing. The surface smoothness, cleanliness, and internal crystal integrity of the wafer directly affect the chip's performance and yield. As integrated circuit manufacturing processes continue to evolve towards smaller linewidths and higher integration densities, the sensitivity and accuracy requirements for defect detection during wafer manufacturing are increasingly stringent. Wafer defects include not only macroscopic problems such as visible surface scratches, particle contamination, and oxide layer inhomogeneity, but also electrically active defects such as lattice dislocations, metallic impurity contamination, microcracks (even if the surface is closed), and uneven diffusion. These defects, under device operating conditions, can lead to reliability issues such as increased leakage current, decreased breakdown voltage, and shortened carrier lifetime, making them key factors affecting chip yield and long-term stability.

[0003] Currently, Automated Optical Inspection (AOI) technology is widely used in microelectronics manufacturing fields such as wafer and printed circuit board manufacturing. AOI systems acquire product images through high-resolution optical imaging modules and use image processing algorithms to compare and analyze the acquired images with preset standard images or design rules, thereby identifying visible or shallow surface defects such as short circuits, open circuits, scratches, and foreign objects. AOI technology overcomes, to a certain extent, the shortcomings of manual visual inspection, such as low efficiency, strong subjectivity, and high missed detection rate. It possesses high inspection speed, repeatability, and standardization, and can effectively detect most appearance defects and some latent defects with obvious optical contrast.

[0004] However, conventional optical inspection equipment cannot effectively detect electrically active defects inside wafers, such as lattice dislocations, metallic contamination, microcracks (even if the surface is closed), and uneven diffusion.

[0005] In view of this, there is an urgent need for a fluorescence detection imaging system and fluorescence detection equipment. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention solves this problem using the following technical structure.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A fluorescence detection imaging system includes: a bright-field fiber, a high-transmittance violet lens group, a Kohler lens group, a dichroic mirror, a semi-reflective semi-transparent lens, an objective lens, a filter, an imaging lens group, and a main camera. The bright-field optical fiber, the high-transmittance violet lens group, the Kohler lens group, and the dichroic mirror are arranged sequentially along the first direction, and the mirror surface of the dichroic mirror is arranged at a 45-degree angle to the first direction. The main camera, imaging lens group, filter, semi-reflective lens and objective lens are arranged sequentially along the first direction. The mirror surface of the semi-reflective lens is arranged parallel to the mirror surface of the dichroic mirror. The semi-reflective lens is arranged in the second direction of the dichroic mirror. The first direction and the second direction are perpendicular to each other.

[0008] It also includes a beam splitter, a retroreflector, and a retroreflector camera. The beam splitter is disposed between the main camera and the imaging lens group. The retroreflector camera and the retroreflector camera are arranged sequentially along the first direction. The mirror surface of the retroreflector camera is set at a 45-degree angle to the first direction. The retroreflector camera is disposed in the second direction of the beam splitter.

[0009] It also includes a dark field disk, which is disposed in a third direction of the dichroic mirror, and the third direction is opposite to the second direction.

[0010] A fluorescence detection device, comprising the aforementioned fluorescence detection imaging system.

[0011] It also includes a mounting base, a carrier, an imaging housing, and a fluorescence housing, wherein the carrier is disposed on the mounting base, and the imaging housing and the fluorescence housing are both disposed on the carrier; The objective lens is disposed below the imaging housing, and the main camera is disposed above the imaging housing; the semi-reflective mirror, the filter, and the imaging lens group are disposed inside the imaging housing; The bright-field optical fiber is disposed at the top of the fluorescent housing, and the high-transmittance violet lens group, the Kohler lens group, and the dichroic mirror are all disposed inside the fluorescent housing.

[0012] A lens assembly frame is rotatably disposed below the imaging housing, and a plurality of objective lenses are disposed thereon. The objective lenses are arranged in a circle on the lens assembly frame, and when the lens assembly frame rotates, the objective lenses pass directly below the imaging lens assembly in sequence.

[0013] The carrier is provided with a first linear module that extends vertically and has an annular light source located on the periphery of the objective lens directly below the imaging lens group.

[0014] The mounting base is provided with a second linear module, which extends in the opposite vertical direction, and the carrier is disposed on the second linear module.

[0015] The carrier is equipped with a displacement sensor, and the detection direction of the displacement sensor is towards the first direction.

[0016] The retroreflector and the retroreflector camera are disposed on one side of the imaging housing, and the beam splitter is disposed inside the imaging housing.

[0017] The following beneficial effects can be achieved by using the structure described above in this invention: In operation, ultraviolet light is introduced through a bright-field optical fiber, passes sequentially through a high-transmittance ultraviolet lens group and a Kohler lens group, is reflected by a dichroic mirror into a semi-reflective lens, is reflected again into the objective lens, and is then irradiated onto the object under test. The fluorescence (visible light) excited by the object under test passes through the objective lens and the semi-reflective lens, and then enters a filter. The filter completely filters out the excited ultraviolet light band, and then passes through an imaging lens group to form an image on the main camera. This enables fluorescence detection of the object under test, and allows for the detection of electrically active defects such as lattice dislocations, metallic impurities, microcracks (even if the surface is closed), and uneven diffusion within the object under test (wafer). This invention enables effective detection of electrically active defects within wafers: It excites the test object (wafer) with ultraviolet light to generate fluorescence, and then uses a filter to completely remove the excitation ultraviolet light band, retaining only the fluorescence signal for imaging on the main camera. Since electrically active defects such as lattice dislocations, metallic impurities, microcracks, and uneven diffusion produce characteristic fluorescence responses under ultraviolet light excitation, which conventional visible light AOI cannot detect, this invention can effectively detect these internal defects, filling a gap in existing optical inspection for wafer internal defect detection. Multi-mode imaging compatibility and enhanced defect identification capabilities: The system integrates two independent illumination sources—bright-field fiber optic and dark-field disk—allowing for flexible switching between bright-field and dark-field illumination modes according to inspection needs. In dark-field mode, with a pure black background, even shallow scratches at the nanometer level or submicron-sized particles can produce bright scattering spots, resulting in an extremely high signal-to-noise ratio and the ability to detect extremely minute defects invisible under bright-field conditions. Combined with fluorescence imaging, it can comprehensively distinguish between surface and internal defects, significantly improving detection coverage and accuracy. Dual-camera synchronous imaging enhances detection efficiency and information richness: By using a beam splitter to disperse the fluorescence signal to the main camera and the image capture camera, simultaneous acquisition of data from both channels within the same field of view can be achieved. The main camera is used for high-resolution, detailed inspection, while the image capture camera can be used for low-magnification overview or synchronous backup, facilitating rapid positioning and verification, balancing detection efficiency and data redundancy, and adapting to the high-throughput requirements of production lines. Rapid switching between multiple magnification objectives adapts to varying precision and field-of-view requirements: A rotatable lens frame is positioned beneath the imaging housing, with multiple objectives of different magnifications arranged circumferentially. Rotation allows the desired objective to be accurately positioned in the optical path. This structure eliminates the need for manual lens replacement, offering rapid switching and reliable positioning. It flexibly addresses different scenarios in wafer inspection, from large-field initial screening to high-magnification fine re-examination, improving operational convenience and equipment versatility. The integrated and compact structural design facilitates production line deployment and maintenance: bright-field fiber, high-transmittance violet lens group, Kohler lens group, dichroic mirror, etc. are integrated into the fluorescent housing, while semi-reflective mirror, filter, imaging mirror group, beam splitter, etc. are integrated into the imaging housing. The two housings are jointly fixed on the carrier to form a modular layout. This design not only improves the stability of the optical path, but also facilitates overall installation, debugging and maintenance, and reduces the space occupied by the equipment, which is beneficial for the online integration of wafer production lines. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of this application; Figure 2 This is a schematic diagram of the structure of Embodiment 2 of this application; Figure 3 This is a schematic diagram of a portion of the structure in Embodiment 2 of this application.

[0019] In the diagram: 1. Bright-field fiber optic cable; 2-3. High-transmittance violet lens group; 4. Kohler lens group; 5. Dichroic mirror; 6. Semi-reflective semi-transparent mirror; 7. Objective lens; 8. Object under test; 9. Filter; 10. Imaging lens group; 11. Beam splitter prism; 12. Main camera; 13. Retroreflector; 14. Retroreflector; 15. Dark-field disk; 16. Mounting base; 17. Carrier; 18. Imaging housing; 19. Fluorescent housing; 20. Lens frame; 21. First linear module; 22. Ring light source; 23. Second linear module; 24. Displacement sensor. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product or device.

[0022] The following is in conjunction with the appendix Figures 1-3 This application will be described in further detail.

[0023] Example 1, Reference Figure 1 The fluorescence detection imaging system shown includes: a bright-field fiber 1, a high-transmittance violet lens group 2-3, a Kohler lens group 4, a dichroic mirror 5 (reflects at 400-650nm and transmits at 785nm), a semi-reflective semi-transparent mirror 6 (400-800nm), an objective lens 7, a filter 9, an imaging lens group 10, and a main camera 12. Among them, the bright-field fiber 1 can be made of multimode silica fiber, which can be precisely connected to the incident end of the high-transmittance ultraviolet lens group 2-3. The fiber input end is connected to an external ultraviolet laser (wavelength 405nm or 450nm, power adjustable range of 50mW to 500mW), and uniform ultraviolet excitation light is introduced through the fiber; The high-transmittance ultraviolet lens group 2-3 can be composed of two independent lenses, referred to as the first lens 2 and the second lens 3, respectively. Both lenses use fused silica substrates and are coated on both sides with anti-reflection coatings in the 400nm-460nm band (transmittance >99.2%). The first lens is a plano-convex lens (focal length f=30mm), and the second lens is a biconcave lens (focal length f=-20mm). The air gap between the two is 5mm, forming a beam expanding and collimating system that expands the diverging spot of the fiber output into a parallel beam with a diameter of approximately 10mm to match the entrance pupil diameter of the subsequent Kohler lens group. The Köhler lens group 4 can consist of a condenser lens and an aperture stop. The condenser lens is an aspherical lens, and the aperture stop is located at the front focal plane of the condenser lens. The diameter of the aperture stop can be continuously adjusted within the range of 2mm to 10mm. The Köhler illumination method ensures a field of view illumination uniformity of >95%, and the numerical aperture of the illumination can be controlled by adjusting the size of the aperture stop, thereby balancing resolution and depth of field. The dichroic mirror 5 can be a long-pass beam splitter with a cutoff wavelength of 450nm. It has a reflectivity >98% in the 400nm–440nm band and a transmittance >95% in the 480nm–800nm ​​band. The lens substrate is B270 optical glass, with dimensions of 25.4mm × 25.4mm × 1.1mm. The mirror surface is fixed at a 45° angle to the first direction (horizontal direction). Ultraviolet light, after being reflected by the dichroic mirror, is redirected to the second direction (vertically downwards) and enters the semi-reflective mirror 6. The semi-reflective mirror 6 can be a broadband beam splitter with a splitting ratio R:T=50:50 (in the range of 400nm to 800nm). Its size is the same as that of the dichroic mirror, and its mirror surface is parallel to that of the dichroic mirror 5 (i.e., it also forms a 45° angle with the horizontal direction). The ultraviolet light from the dichroic mirror 5 is reflected again by the semi-reflective mirror 6 and passes vertically downward through the objective lens 7 to illuminate the test object 8. At the same time, the fluorescence (visible light band, with a main peak wavelength of about 520nm to 620nm) generated by the test object 8 passes upward through the objective lens 7, and the semi-reflective mirror 6 transmits 50% of the light energy into the upper imaging optical path. Objective 7 can be an infinity-corrected fluorescence objective with a working distance, offering magnifications of 5×, 10×, 20×, and 50×, numerical apertures of 0.12, 0.25, 0.45, and 0.75, and working distances of 20mm, 15mm, 10mm, and 5mm, respectively. Its threaded interface conforms to the RMS standard, and its parfocal distance is 45mm. The entrance pupil of objective 7 and the exit pupil of Kohler lens group 4 are conjugate, achieving telecentric illumination on the object side and ensuring consistent illumination at the edge and center of the field of view. Filter 9 can be a band-stop notch filter with a center wavelength of 405nm or 450nm (matching the excitation source), a half-width of 10nm, and an optical density OD>6 (i.e., transmittance <10). -6 The passband range is 480nm~800nm, and the average transmittance is >92%. The filter 9 is installed in the optical path directly above the semi-reflective mirror 6, and its mirror surface is perpendicular to the optical path. It is used to completely filter out the ultraviolet light background generated by the excitation light and only allow the fluorescence signal to pass through. The imaging lens group 10 can consist of three lenses (two cemented doublet achromatic lenses and one plan-corrected lens), with an equivalent focal length of f=100mm, an image-side numerical aperture NA=0.1, and an image circle diameter ≥18mm, suitable for a 1-inch target surface camera. The imaging lens group 10 focuses the fluorescence signal from the filter 9 onto the photosensitive surface of the main camera 12, and the total system magnification is the product of the objective lens magnification and the lens group magnification (1×).

[0024] Among them, the bright field fiber 1, the high-transmittance violet light lens group 2-3, the Kohler lens group 4 and the dichroic mirror 5 are arranged in sequence along the first direction, and the mirror surface of the dichroic mirror 5 is arranged at a 45-degree angle with the first direction. The main camera 12, imaging lens group 10, filter 9, semi-reflective mirror 6 and objective lens 7 are arranged sequentially along the first direction. The mirror surface of the semi-reflective mirror 6 is arranged parallel to the mirror surface of the dichroic mirror 5. The semi-reflective mirror 6 is arranged in the second direction of the dichroic mirror 5. The first direction and the second direction are perpendicular to each other.

[0025] Based on the above structure, in use, ultraviolet light is introduced through bright-field fiber 1, passes sequentially through high-transmittance ultraviolet lens group 2-3 and Kohler lens group 4, is reflected by dichroic mirror 5 into semi-reflective mirror 6, is reflected again into objective lens 7, and is then irradiated onto the test object 8. The fluorescence (visible light) excited by the test object 8 passes through objective lens 7 and semi-reflective mirror 6 and enters filter 9. Filter 9 completely filters out the excited ultraviolet light (405nm or 450nm) band, and then passes through imaging lens group 10 to image onto main camera 12; thereby realizing fluorescence detection of the test object 8, and realizing the detection of electrically active defects such as lattice dislocations, metal impurities, microcracks (even if the surface is closed), and uneven diffusion inside the test object 8 (wafer).

[0026] This embodiment also includes a beam splitter 11, a retroreflector 13, and a retroreflector camera 14. The beam splitter 11 is positioned between the main camera 12 and the imaging lens group 10. The retroreflector camera 14 and the retroreflector 13 are arranged sequentially along a first direction. The mirror surface of the retroreflector 13 is set at a 45-degree angle to the first direction. The retroreflector 13 is positioned in a second direction along the beam splitter 11. The fluorescence after passing through the imaging lens group 10 is split by the beam splitter 11, reaches the retroreflector 13, and is finally imaged onto the retroreflector camera 14. By splitting the fluorescence signal to the main camera and the retroreflector camera through the beam splitter prism, dual-channel synchronous acquisition under the same field of view can be achieved. The main camera is used for high-resolution fine inspection, while the retroreflector camera can be used for low-magnification overview or synchronous backup, facilitating rapid positioning and verification, balancing inspection efficiency and data redundancy, and adapting to the high-throughput requirements of the production line.

[0027] This embodiment also includes a dark field disk 15, which is a ring fiber coupler with an integrated ring optical fiber bundle inside. Its output ends are arranged in a ring, and the output light direction converges at the center of the dichroic mirror 5. The incident end of the dark field disk 15 is connected to an independent ultraviolet light source. The dark field disk 15 is set in the third direction of the dichroic mirror 5. The third direction is opposite to the second direction. The ultraviolet light is introduced by the dark field disk 15, reflected by the dichroic mirror 5 and enters the semi-reflective mirror 6. After reflection, it enters the objective lens 7 and is then irradiated onto the test object 8. The fluorescence (visible light) excited by the test object 8 passes through the objective lens 7 and the semi-reflective mirror 6 and enters the filter 9. The filter 9 completely filters out the excited ultraviolet light (405nm or 450nm) band. Then, it is imaged onto the main camera 12 by the imaging lens group 10, thus realizing dark field imaging. Since the background is pure black, as long as there are tiny scattering points (such as shallow scratches at the nanometer level or submicron particles), bright "bright spots" will be produced on the black background. Therefore, the signal-to-noise ratio of dark field imaging is extremely high, and it can detect extremely fine defects that are not visible under bright field conditions.

[0028] Example 2: A fluorescence detection device, including the fluorescence detection imaging system described in Example 1.

[0029] This embodiment also includes a mounting base 16, a carrier 17, an imaging housing 18, and a fluorescent housing 19. The carrier 17 is disposed on the mounting base 16, and the imaging housing 18 and the fluorescent housing 19 are both disposed on the carrier 17. Mounting base 16 can be made of cast aluminum alloy with locating pin holes and M8 threaded mounting holes on the bottom surface for easy fixing to a linear motion platform or air-bearing vibration isolation platform. The upper surface of mounting base 16 is precision milled to a flatness better than 0.02mm, serving as a reference mounting surface for other components; The imaging housing 18 is a rectangular, sealed metal box (made of 6061 aluminum alloy, with a wall thickness of 5mm, and the interior is blackened to reduce stray light), which is fixed to the carrier 17 with bolts. The top opening of the imaging housing 18 is used to mount the main camera 12 and the rewind camera 14 via a flange, and the bottom has a light-transmitting hole for mounting the objective lens 7. Inside the imaging housing 18, a semi-reflective mirror 6, a filter 9, an imaging lens group 10, and a beam splitter 11 are fixed vertically in sequence. All components are mounted using a precision frame (with three-dimensional adjustment function), which allows for pitch, yaw, and fine-tuning of the center position during assembly and adjustment. The fluorescent housing 19 is a cylindrical, sealed structure (made of the same material as the imaging housing), fixed to the carrier 17 by bolts. A bright-field fiber optic cable 1 is installed at the top opening, and a dark-field disk 15 is installed at the side opening. Inside the fluorescent housing 19, a high-transmittance ultraviolet lens group 2-3, a Kohler lens group 4, and a dichroic mirror 5 are sequentially fixed along the horizontal direction. Each component is also equipped with a precision adjustment frame. A light-transmitting hole is opened on the adjacent sidewall between the fluorescent housing 19 and the imaging housing 18, allowing ultraviolet light reflected by the dichroic mirror 5 to pass through the light-transmitting hole and enter the semi-reflective lens 6 inside the imaging housing 18. A dustproof optical window (double-sided anti-reflective coating) can be installed at the light-transmitting hole to ensure that the two housings are independently sealed. Based on the above, the imaging system is integrated and assembled using the imaging housing 18 and the fluorescence housing 19. Both the imaging housing 18 and the fluorescence housing 19 are mounted on the carrier 17 to facilitate synchronous adjustment of the imaging elements within the imaging housing 18 and the fluorescence housing 19. In use, the object under test 8 is placed on the equipment platform, with the object under test 8 located directly below the imaging housing 18. The bright-field fiber 1 introduces ultraviolet light, which, after passing through the imaging system, is imaged onto the main camera 12, thereby realizing fluorescence detection of the object under test 8 and enabling the detection of electrically active defects such as lattice dislocations, metallic impurities, microcracks (even if the surface is closed), and uneven diffusion inside the object under test 8 (wafer).

[0030] The retroreflector 13 and the retroreflector camera 14 are disposed on one side of the imaging housing 18, and the beam splitter 11 is disposed inside the imaging housing 18. The beam splitter 11 splits the fluorescence signal to the main camera and the retroreflector camera, enabling dual-channel synchronous acquisition in the same field of view. The main camera is used for high-resolution fine inspection, while the retroreflector camera can be used for low-magnification overview or synchronous backup, facilitating rapid positioning and verification, balancing inspection efficiency and data redundancy, and adapting to the high-throughput requirements of the production line. The dark field disk 15 is located on one side of the fluorescent housing 19; it integrates two independent illumination sources, a bright field fiber optic and a dark field disk, allowing for flexible switching between bright field and dark field illumination modes according to detection needs. In dark field mode, the background is pure black, and even shallow scratches at the nanometer level or submicron-sized particles can produce bright scattering spots with an extremely high signal-to-noise ratio, enabling the detection of extremely fine defects invisible under bright field conditions; combined with fluorescence imaging, it can comprehensively distinguish between surface and internal defects, significantly improving detection coverage and accuracy.

[0031] like Figure 2 and Figure 3 As shown, a mirror frame 20 is rotatably mounted below the imaging housing 18. The mirror frame 20 is a disc-shaped turntable, which is mounted on the bottom of the imaging housing 18 via precision crossed roller bearings. Several objective lenses 7 are provided, each with a different magnification. The objective lenses 7 are arranged in a circle on the mirror frame 20. When the mirror frame 20 rotates, the objective lenses 7 pass directly below the imaging mirror group 10 in sequence. Thus, according to the usage requirements, the mirror frame 20 is rotated so that the objective lens 7 of the corresponding magnification is placed in the optical path of the imaging system, satisfying diverse detection needs.

[0032] like Figure 2 and Figure 3 As shown, a first linear module 21 is provided on the carrier 17. The first linear module 21 extends vertically and uses a miniature linear guide rail in conjunction with a stepper motor and a lead screw. A ring light source 22 is provided on the first linear module 21. The ring light source 22 is located on the periphery of the objective lens 7 directly below the imaging lens group 10. The ring light source 22 illuminates the object 8 under test, making the image clearer. When the objective lens 7 needs to be replaced, the ring light source 22 is driven downward by the first linear module 21 to avoid the rotation of the objective lens 7. The first linear module 21 can adjust the height of the ring light source 22 to meet different lighting requirements.

[0033] like Figure 2As shown, a second linear module 23 is provided on the mounting base 16. The second linear module 23 extends in the opposite vertical direction. The carrier 17 is set on the second linear module 23 and is driven by a high-precision ball screw (lead 5mm, repeatability ±1μm) in conjunction with a servo motor. The stroke range is 0~100mm. It is used to drive the carrier 17 to lift and lower as a whole, so as to adjust the working distance and initial focus for test objects of different thicknesses (wafer thickness is commonly 0.3mm~1.2mm). The carrier 17 is driven to lift and lower by the second linear module 23, thereby adjusting the height of the imaging system to adapt to different detection needs.

[0034] like Figure 2 As shown, a displacement sensor 24 is provided on the carrier 17. The detection direction of the displacement sensor 24 is towards the first direction. The displacement sensor 24 is preferably a spectral confocal displacement sensor to detect the object 8 below. Its detection direction is consistent with the imaging optical path direction. It can sense the distance change on the surface of the object in real time, providing accurate feedback for automatic focusing or height tracking. This maintains stable image clarity in batch detection, reduces deviation caused by manual focusing, and improves the repeatability and reliability of the detection results.

[0035] During actual inspection, the wafer is transported to the area directly below the objective lens 7 via a robotic arm or conveyor belt. The displacement sensor 24 provides real-time height information, and the second linear module 23 automatically adjusts the height of the carrier 17 to ensure precise positioning of the objective lens 7. The controller then selects a bright-field / dark-field / fluorescence mode based on a preset formula—for example, first, a low-magnification (5×) bright-field mode is used to quickly scan the entire wafer and locate suspicious areas; then, a high-magnification (20× or 50×) fluorescence mode is switched for detailed inspection. The main camera 12 acquires fluorescence images, and the recovery camera 14 simultaneously acquires low-resolution panoramic images for position mapping. The images are transmitted to an industrial control computer via the GigE interface. Built-in deep learning or traditional image processing algorithms identify and classify the fluorescence intensity distribution and defect morphology. The inspection results are displayed in real-time and recorded in a database.

[0036] After completing the inspection of a batch of wafers, the system can automatically switch to dark field mode for spot checks to verify the presence of extremely fine surface defects. Throughout the inspection process, the first linear module 21 can automatically adjust the height of the ring light source 22 according to the reflective characteristics of the surface of the object being inspected. When the overall image brightness is detected to be too low or overexposed, the PWM duty cycle is adjusted through a PID closed loop to maintain stable image quality.

[0037] In summary, this application has the following advantages: This invention enables effective detection of electrically active defects within wafers: It excites the test object (wafer) with ultraviolet light to generate fluorescence, and then uses a filter to completely remove the excitation ultraviolet light band, retaining only the fluorescence signal for imaging on the main camera. Since electrically active defects such as lattice dislocations, metallic impurities, microcracks, and uneven diffusion produce characteristic fluorescence responses under ultraviolet light excitation, which conventional visible light AOI cannot detect, this invention can effectively detect these internal defects, filling a gap in existing optical inspection methods for detecting internal wafer defects.

[0038] Multi-mode imaging compatibility and enhanced defect identification capabilities: The system integrates two independent illumination sources—a bright-field fiber optic cable and a dark-field disk—allowing for flexible switching between bright-field and dark-field illumination modes to meet specific inspection needs. In dark-field mode, with a pure black background, even shallow scratches at the nanometer level or submicron-sized particles can produce bright scattering spots, resulting in an extremely high signal-to-noise ratio and enabling the detection of extremely minute defects invisible under bright-field conditions. Combined with fluorescence imaging, it can comprehensively distinguish between surface and internal defects, significantly improving detection coverage and accuracy.

[0039] Dual-camera synchronous imaging enhances detection efficiency and information richness: A beam-splitting prism disperses the fluorescence signal to both the main camera and the image capture camera, enabling simultaneous acquisition across two channels within the same field of view. The main camera is used for high-resolution, detailed inspection, while the image capture camera can be used for low-magnification overviews or synchronous backup, facilitating rapid positioning and verification. This balances detection efficiency with data redundancy, adapting to the high-throughput requirements of production lines.

[0040] Rapid switching between multiple magnification objectives adapts to varying precision and field-of-view requirements: A rotatable lens frame is positioned beneath the imaging housing, with multiple objectives of different magnifications arranged circumferentially. Rotation allows the desired magnification objective to be accurately positioned in the optical path. This structure eliminates the need for manual lens replacement, offering rapid switching and reliable positioning. It flexibly addresses different scenarios in wafer inspection, from large-field initial screening to high-magnification fine re-examination, enhancing operational convenience and equipment versatility.

[0041] The integrated and compact structural design facilitates production line deployment and maintenance: bright-field fiber, high-transmittance violet lens group, Kohler lens group, dichroic mirror, etc. are integrated into the fluorescent housing, while semi-reflective mirror, filter, imaging mirror group, beam splitter, etc. are integrated into the imaging housing. The two housings are jointly fixed on the carrier to form a modular layout. This design not only improves the stability of the optical path, but also facilitates overall installation, debugging and maintenance, and reduces the space occupied by the equipment, which is beneficial for the online integration of wafer production lines.

[0042] Flexible height adjustment and ring illumination ensure image quality: The equipment is equipped with a second linear module to drive the carrier to lift and lower, which can adjust the overall height of the imaging system to adapt to the test objects of different thicknesses or different working distance requirements; at the same time, a height-adjustable ring light source is set around the objective lens, which can adjust the lighting angle and height according to the surface characteristics of the test object, enhance the display of surface details, and automatically avoid interference when changing objective lenses, thereby improving imaging consistency and the degree of automation of operation.

[0043] Displacement sensing assists autofocus and improves detection repeatability: A spectral confocal displacement sensor is set on the carrier. Its detection direction is consistent with the imaging optical path direction. It can sense the distance change on the surface of the object in real time, providing accurate feedback for autofocus or height tracking. This keeps the image clarity stable in batch detection, reduces the deviation caused by manual focusing, and improves the repeatability and reliability of the detection results.

[0044] The above are merely preferred embodiments of this application, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations that are directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A fluorescence detection imaging system, characterized in that, include: Brightfield fiber (1), high-transmittance violet light lens group (2-3), Kohler lens group (4), dichroic mirror (5), semi-reflective semi-transparent mirror (6), objective lens (7), filter (9), imaging lens group (10) and main camera (12); The bright-field optical fiber (1), the high-transmittance violet lens group (2-3), the Kohler lens group (4) and the dichroic mirror (5) are arranged sequentially along the first direction, and the mirror surface of the dichroic mirror (5) is arranged at a 45-degree angle with the first direction. The main camera (12), imaging lens group (10), filter (9), semi-reflective lens (6) and objective lens (7) are arranged sequentially along the first direction. The mirror surface of the semi-reflective lens (6) is arranged parallel to the mirror surface of the dichroic mirror (5). The semi-reflective lens (6) is arranged in the second direction of the dichroic mirror (5). The first direction and the second direction are perpendicular to each other.

2. The fluorescence detection imaging system according to claim 1, characterized in that: It also includes a beam splitter (11), a retroreflector (13), and a retroreflector (14). The beam splitter (11) is disposed between the main camera (12) and the imaging lens group (10). The retroreflector (14) and the retroreflector (13) are arranged sequentially along the first direction. The mirror surface of the retroreflector (13) is set at a 45-degree angle with the first direction. The retroreflector (13) is disposed in the second direction of the beam splitter (11).

3. The fluorescence detection imaging system according to claim 2, characterized in that: It also includes a dark field disk (15), which is disposed in a third direction of the dichroic mirror (5), and the third direction is opposite to the second direction.

4. A fluorescence detection device, characterized in that: Includes the fluorescence detection imaging system as described in claim 3.

5. The fluorescence detection device according to claim 4, characterized in that: It also includes a mounting base (16), a carrier (17), an imaging housing (18), and a fluorescence housing (19), wherein the carrier (17) is disposed on the mounting base (16), and the imaging housing (18) and the fluorescence housing (19) are both disposed on the carrier (17); The objective lens (7) is located below the imaging housing (18), and the main camera (12) is located above the imaging housing (18); the semi-reflective mirror (6), the filter (9), and the imaging lens group (10) are located inside the imaging housing (18). The bright-field optical fiber (1) is disposed on the top of the fluorescent housing (19), and the high-transmittance violet lens group (2-3), the Kohler lens group (4) and the dichroic mirror (5) are all disposed inside the fluorescent housing (19).

6. The fluorescence detection device according to claim 5, characterized in that: A lens frame (20) is rotatably disposed below the imaging housing (18). Several objectives (7) are disposed thereon, and the objectives (7) are arranged in a circle on the lens frame (20). When the lens frame (20) rotates, the objectives (7) pass directly below the imaging lens group (10) in sequence.

7. A fluorescence detection device according to claim 6, characterized in that: The carrier (17) is provided with a first linear module (21), which extends in the vertical direction. The first linear module (21) is provided with a ring light source (22), which is located on the periphery of the objective lens (7) directly below the imaging lens group (10).

8. A fluorescence detection device according to claim 5, characterized in that: The mounting base (16) is provided with a second linear module (23), the second linear module (2) extends in the opposite vertical direction, and the carrier (17) is provided on the second linear module (23).

9. A fluorescence detection device according to claim 8, characterized in that: A displacement sensor (24) is provided on the carrier (17), and the detection direction of the displacement sensor (24) is towards the first direction.

10. A fluorescence detection device according to claim 5, characterized in that: The retroreflector (13) and the retroreflector (14) are disposed on one side of the imaging housing (18), and the beam splitter (11) is disposed inside the imaging housing (18).

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