Wafer defect detection system and method

Abstract

The invention provides a wafer defect detection system and method. The detection system comprises a first light source channel, a second light source channel, a reflection detection channel, a vertical detection channel, a scattering detection channel and a motion platform. According to the wafer defect detection system provided by the invention, large-size surface topography is measured through the reflection detection channel, and small height difference and small-diameter defects can be measured through bright field detection of the vertical detection channel; the five scattering measurement channels can simultaneously detect near-infrared, visible light, inclined incident light source, near-ultraviolet and vertical incident light source wave band energy of the wafer, and can accurately detect various defects of the wafer. Defects are identified and accurately classified, sources and evolution processes of the defects are traced, and corresponding data support is provided for improvement of a wafer manufacturing process.

Description

Technical Field

[0001] The present invention relates to the field of wafer detection technology, and in particular to a wafer defect detection system and method. Background Art

[0003] Wafer defect detection is a crucial part of semiconductor manufacturing. Wafer defect detection technology helps improve the yield of chip manufacturing, improve production efficiency and reduce production costs. Wafers are prone to various defects such as particles, scratches, cracks, stains, pits, and bumps during the production process. These defects can affect the function and performance of the chip and even cause the chip to fail. Therefore, it is very necessary to effectively detect and analyze wafer defects.

[0004] As the third-generation semiconductor material wafers represented by silicon carbide are increasingly widely used in the industrial field, it is particularly important to effectively identify the defects of third-generation semiconductor wafers represented by silicon carbide, and then classify the defects and trace the change process of the defects. This can not only guide the improvement direction of the process technology, but also effectively reduce the production cost of the wafer and improve the final performance of the device. Wafers such as silicon carbide not only have common defects such as particles, scratches, cracks, stains, pits, protrusions, etc., but also crystal defects such as triangles, carrot defects, stacking faults and basal plane dislocations.

[0005] The wafer defect detection system provided by the present invention utilizes integrated surface scattering measurement, reflection measurement and photoluminescence detection technology to capture various key defects, such as particles, scratches, cracks, stains, pits, protrusions, triangles, carrot defects, stacking faults and basal plane dislocations, etc., providing an effective detection means for the detection of third-generation semiconductor wafers represented by silicon carbide. Summary of the invention

[0007] In view of some or all of the problems in the prior art, the present invention provides a wafer defect detection system in a first aspect, comprising: A first light source channel, a second light source channel, a reflection detection channel, a vertical detection channel, a scattering detection channel, and a motion platform; The first light source channel includes a first laser and a first light source modulation component, and the first laser emits a first light source; The second light source channel includes a second laser and a second light source modulation component, and the second laser emits a second light source; The reflection detection channel includes a reflection modulation component and a four-quadrant detector, and the reflection detection channel is configured to collect the inclined reflection light beam of the wafer, and the inclined reflection light beam is modulated by the reflection modulation component and incident on the four-quadrant detector; The vertical detection channel includes an array detector, and the vertical detection channel is configured to collect a vertical reflected light beam of the wafer, and the vertical reflected light beam is incident on the array detector after being modulated by a second light source modulation component; The scattering detection channel includes a reflective objective lens and a scattering measurement channel, wherein the reflective objective lens is configured to collect a scattered light beam of the wafer, and the scattered light beam is focused and incident on the scattering measurement channel after passing through the reflective objective lens; The motion platform is configured to secure a wafer and selectively actuate the wafer so as to perform a scanning process using the first light source and the second light source.

[0008] Furthermore, the wafer defect detection system also includes a controller, which is configured to control the movement of the motion platform, process the signals obtained by the array detector, the four-quadrant detector and the scattering measurement channel and transmit the signals to a computer to generate an image of the wafer, the output ends of the array detector, the four-quadrant detector and the scattering measurement channel are connected to the input end of the controller, and the output end of the controller is externally connected to the computer.

[0009] Further, the first light source modulation assembly includes a lens, a reflector, an aperture and a half-wave plate; After being modulated by the first light source modulation component, the first light source is focused along a first direction and obliquely incident onto the surface of the wafer, and the angle of the oblique incidence is ≥55 degrees to the direction perpendicular to the surface of the wafer.

[0010] Further, the second light source modulation assembly includes an optical isolator, an aperture, a lens, a reflector, a polarization beam splitter, a DIC prism and a half wave plate; The DIC prism is used to split the incoming linearly polarized light beam into two independent orthogonal polarized light beams; After being modulated by the second light source modulation component, the second light source is focused along a second direction and incident on the surface of the wafer, and the angle of incidence is perpendicular to the surface of the wafer.

[0011] Further, the reflective modulation assembly includes a lens, a reflector, an aperture, a neutral density filter, a quarter wave plate and a Wollaston prism; The four-quadrant detector is used to measure the energy of the inclined reflected light beam and the position where the laser spot is irradiated on the four-quadrant detection, and the position where the laser spot is irradiated on the four-quadrant detection is used to measure the changes caused by the change of the wafer surface morphology; The thin film contamination on the wafer is determined by measuring the energy on different four-quadrant photodetectors.

[0012] Further, the scattered light beam includes scattering by a first light source, scattering by a second light source, and photoluminescence scattering; The photoluminescence scattering includes visible light-photoluminescence scattering, near ultraviolet-photoluminescence scattering and near infrared-photoluminescence scattering; The scattering measurement channels include a first light source scattering measurement channel, a second light source scattering measurement channel, a visible light-photoluminescence scattering measurement channel, a near ultraviolet-photoluminescence scattering measurement channel, and a near infrared-photoluminescence scattering measurement channel; The first light source scattering measurement channel includes a dichroic mirror, an aperture, a filter and a photomultiplier tube; The second light source scattering measurement channel includes a reflector, an aperture, a filter and a photomultiplier tube; The visible light-photoluminescence scattering measurement channel includes a dichroic mirror, an aperture, a filter and a photomultiplier tube; The near-ultraviolet-photoluminescence scattering measurement channel includes a dichroic mirror, an aperture, a filter and a photomultiplier tube; The near-infrared-photoluminescence scattering measurement channel includes a dichroic mirror, an aperture, a filter, and a photomultiplier tube; detecting one or more scattering defects based on the characteristics measured by at least one of the five scattering measurement channels; One or more photoluminescent defects are detected based on the characteristics measured by at least one of the five scattering measurement channels.

[0013] Further, the motion platform includes a rotating platform and a translation platform; The motion platform is configured to scan in a spiral mode, or to scan in a circular plus stepping mode, or in an XY scanning mode.

[0014] A second aspect of the present invention provides a wafer defect detection method, comprising: directing a light beam from a first light source onto a surface of the wafer along a first direction; directing a light beam from a second light source onto the surface of the wafer along a second direction; Collecting the tilted reflected light beam from the wafer, measuring the energy of the tilted reflected light beam through a four-quadrant detector to determine the defects on the wafer, determining the topography on the wafer or correcting the height change of the wafer by irradiating the laser spot on the position of the four-quadrant detection, and determining the film contamination on the wafer by measuring the energy on different four-quadrant photoelectric detectors; Collect vertical reflected beams from the wafer and detect small height differences and small diameter defects through array detectors; collecting scatter from a wafer, the scatter comprising at least one of elastic scatter caused by one or more defects of the wafer or photoluminescent scatter emitted by one or more photoluminescent defects of the wafer; Separating the scattering from the wafer into a first light source band, a second light source band, a visible light band, a near ultraviolet band, and a near infrared band; measuring one or more characteristics of at least one of the first light source band, the second light source band, the visible light band, the near ultraviolet band, and the near infrared band; detecting one or more scattering defects based on the one or more characteristics; One or more photoluminescent defects are detected based on the one or more characteristics.

[0015] Furthermore, the contamination of the thin film on the wafer is determined by calculating the difference in voltage values ​​corresponding to the energies on different four-quadrant photoelectric detectors.

[0016] Furthermore, the wafer to be inspected is scanned, and a defect distribution map is formed based on defect information corresponding to each scanning position and scanning coordinate information.

[0017] The technical solution of the present invention has the following beneficial effects: 1. The wafer defect detection system provided by the present invention adopts two light sources, and the illumination angles of the light sources include oblique incident illumination and vertical incident illumination, with short scanning and measurement time and high efficiency.

[0018] 2. The wafer defect detection system provided by the present invention is compatible with surface defect detection of opaque wafers (such as silicon wafers) and transparent or semi-transparent wafers (such as silicon carbide and gallium nitride), which broadens the application scenarios of the system.

[0019] 3. The wafer defect detection system provided by the present invention has five measurement channels: first light source scattering, second light source scattering, visible light-photoluminescence scattering, near ultraviolet-photoluminescence scattering and near infrared-photoluminescence scattering, which can more accurately detect various defects of the wafer.

[0020] 4. The wafer defect detection system provided by the present invention has five scattering measurement channels, which can simultaneously detect the energy of the first light source, the second light source, visible light, near ultraviolet light and near infrared bands of the wafer. The five measurement channels use photomultiplier tubes as photoelectric detectors, which have extremely high photoelectric sensitivity and can effectively detect the energy of faint light.

[0021] 5. The wafer defect detection system provided by the present invention can not only measure the surface morphology of larger sizes through the reflection detection channel, but also measure small height differences and small diameter defects through bright field detection of the vertical detection channel.

[0022] 6. The wafer defect detection system provided by the present invention can not only detect the wafer morphology, but also perform defocus compensation, thereby significantly improving the defect measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] To further illustrate the above and other advantages and features of various embodiments of the present invention, a more specific description of various embodiments of the present invention will be presented with reference to the accompanying drawings. It will be understood that these drawings only depict typical embodiments of the present invention and are therefore not to be considered as limiting the scope thereof. In the accompanying drawings, for clarity, identical or corresponding parts will be represented by identical or similar reference numerals.

[0025] Figure 1 A schematic diagram of a wafer defect detection system according to an embodiment of the present invention; Figure 2 A schematic diagram of a wafer defect detection system according to another embodiment of the present invention; Figure 3a-3c A schematic diagram of wafer scanning and imaging performed by a motion platform according to an embodiment of the present invention; Figure 4 A schematic diagram of four photosensitive areas of a four-quadrant detector according to an embodiment of the present invention; Figure 5 A schematic diagram of the position change of the laser spot on the four-quadrant detector caused by the change of the wafer surface according to an embodiment of the present invention; Figure 6 A schematic diagram of a position change of a laser spot on a four-quadrant detector caused by a circumferential or radial surface change of a wafer according to an embodiment of the present invention; Figure 7 A surface topography image of a wafer and a schematic diagram of slope variation of a defective cross section according to an embodiment of the present invention; Figure 8 A schematic diagram of the defocus correction principle of an embodiment of the present invention; Figure 9a-9b A schematic diagram of a thin film detection principle according to an embodiment of the present invention; Fig.10 A schematic diagram of a propagation path of a light beam in a DIC prism according to an embodiment of the present invention; Fig.11 A schematic diagram of the position of a light spot in an array detector according to an embodiment of the present invention; Figure 12a-12h A schematic diagram of light beam scattering on a wafer surface according to an embodiment of the present invention; Figure 13a-13b A schematic diagram of a reflective objective lens collecting scattered light from a wafer according to an embodiment of the present invention; Fig.14 A schematic diagram of a photoluminescence radiation spectrum of a region without photoluminescence defects in a wafer according to an embodiment of the present invention; Fig.15 A schematic diagram of a photoluminescence radiation spectrum of a photoluminescence defect region in a wafer according to an embodiment of the present invention; Fig.16A schematic diagram of a reflective detection channel detecting a transparent or semi-transparent wafer according to an embodiment of the present invention; Fig.17 A schematic diagram of a scattering detection channel detecting a transparent or semi-transparent wafer according to an embodiment of the present invention; Fig.18 The figure is a schematic flow chart of a wafer defect detection method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In the following description, the present invention is described with reference to various embodiments. However, those skilled in the art will recognize that various embodiments may be implemented without one or more specific details or with other replacement and / or additional methods or components. In other cases, well-known structures or operations are not shown or described in detail to avoid obscuring the inventive point of the present invention. Similarly, for the purpose of explanation, specific numbers and configurations are set forth to provide a comprehensive understanding of embodiments of the present invention. However, the present invention is not limited to these specific details.

[0028] In the description of the present invention, it should be noted that the terms "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0029] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "configuration", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] It should be noted that it should also be understood that in the embodiments of the present invention, the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the existence of stated features, elements and / or parts, but do not exclude the existence or addition of one or more other features, elements, parts and / or combinations thereof.

[0031] In this specification, the quantifiers "plurality" and "multiple" refer to one or more than one element.

[0032] In this specification, reference to "one embodiment" or "the embodiment" means that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present invention. The phrase "in one embodiment" appearing in various places in this specification does not necessarily all refer to the same embodiment.

[0033] It should be noted that the embodiments of the present invention describe the method steps in a specific order, but this is only for the purpose of illustrating the specific embodiment, rather than limiting the order of the steps. On the contrary, in different embodiments of the present invention, the order of the steps can be adjusted according to actual needs.

[0034] The present invention will be described in detail below with reference to the accompanying drawings. Figure 1 FIG. 1 is a schematic diagram of a wafer defect detection system according to an embodiment of the present invention. Figure 1As shown, the wafer defect detection system includes: a first light source channel, a second light source channel, a reflection detection channel, a vertical detection channel, a scattering detection channel, and a motion platform. The first light source channel includes a first laser 101 and a first light source modulation component. The first light source modulation component includes a first lens 102, a first aperture 103, a second lens 104, a first half-wave plate 106, a first reflector 107, and a third lens 108. The first laser 101 emits a first light source, which is modulated by the first light source modulation component into a first light source beam, i.e., an inclined incident beam 109, which is incident on the surface of the wafer 501 at the focus 110. The second light source channel includes a second laser 301 and a second light source modulation component. The second light source modulation component includes an optical isolator 302, a second half-wave plate 303, a polarization beam splitter 304, a DIC prism 305, a sixth lens 306, a third aperture 307, a seventh lens 308, an eighth lens 310, a third reflector 311, and a fourth reflector 312. The second laser 301 emits a second light source, which is modulated by the second light source modulation component into a second light source beam, i.e., a vertical incident beam 313, which is incident on the surface of the wafer 501. The reflection detection channel includes a reflection modulation component and a four-quadrant detector (QD). The reflection modulation component includes a fourth lens 201, a second reflector 202, a second aperture 203, a neutral density filter 204, a quarter-wave plate 205, and a Wollaston prism 206. The four-quadrant detector includes a first four-quadrant detector 207 and a second four-quadrant detector 208. The reflection detection channel is configured to collect the inclined reflection beam 209 of the wafer, which is incident on the four-quadrant detector after being modulated by the reflection modulation component. The vertical detection channel includes an array detector, which is configured to collect the vertical reflection beam of the wafer, which is incident on the array detector 314 after being modulated by the second light source modulation component. The scattering detection channel includes a reflective objective 401 and a scattering measurement channel. The scattering measurement channel includes five measurement channels, namely, a near infra-red photoluminescence (NIR-PL) scattering measurement channel 428, a visible light-photoluminescence (VIS-PL) scattering measurement channel 429, a first light source scattering measurement channel 430, a near ultraviolet photoluminescence (NUV-PL) scattering measurement channel 431 and a second light source scattering measurement channel 432.The NIR-PL scattering measurement channel 428 includes a first dichroic mirror 402, a fourth aperture 407, a first filter 412, and a first photomultiplier tube (PMT) 417. The VIS-PL scattering measurement channel 429 includes a second dichroic mirror 403, a fifth aperture 408, a second filter 413, and a second PMT 418. The first light source scattering measurement channel 430 includes a third dichroic mirror 404, a sixth aperture 409, a third filter 414, and a third PMT 419. The NUV-PL scattering measurement channel 431 includes a fourth dichroic mirror 405, a seventh aperture 410, a fourth filter 415, and a fourth PMT 420. The second light source scattering measurement channel 432 includes a fifth reflector 406, an eighth aperture 411, a fifth filter 416, and a fifth PMT 421. The reflective objective lens 401 is configured to collect the scattered light beam 427 of the wafer, and the scattered light beam 427 is focused and incident on the scattering measurement channel after passing through the reflective objective lens 401. The motion platform includes a rotating table 601 and a displacement table 602, which are configured to fasten the wafer and selectively actuate the wafer so as to perform a scanning process using the first light source and the second light source. The movement of the rotating table 601 can be a rotation in the XY plane, or can include displacement of the X axis and the Y axis. The displacement table 602 can be a Z-axis moving table. The wafer 501 is placed on the surface of the rotating table 601, and the wafer 501 includes a wafer upper surface 5011 and a wafer lower surface 5012. In one embodiment of the present invention, the wafer defect detection system also includes a controller, which is configured to control the movement of the motion platform, process the signals obtained by the array detector, the four-quadrant detector and the scattering measurement channel and transmit the signals to a computer to generate an image of the wafer, and the output ends of the array detector, the four-quadrant detector and the scattering measurement channel are connected to the input end of the controller, and the output end of the controller is externally connected to the computer.

[0035] Figure 2 FIG. 4 is a schematic diagram of a wafer defect detection system according to another embodiment of the present invention. Figure 2 The embodiment shown and Figure 1Compared with the embodiment, in the reflection detection channel and the scattering measurement channel, a lens is added before the aperture to better focus the light beam and facilitate subsequent detection. Specifically, the reflection detection channel adds a fifth lens 210 between the fourth lens 201 and the second aperture 203; the NIR-PL scattering measurement channel 428 adds a ninth lens 422 between the first dichroic mirror 402 and the fourth aperture 407; the VIS-PL scattering measurement channel 429 adds a tenth lens 423 between the second dichroic mirror 403 and the fifth aperture 408; the first light source scattering measurement channel 430 adds an eleventh lens 424 between the third dichroic mirror 404 and the sixth aperture 409; the NUV-PL scattering measurement channel 431 adds a twelfth lens 425 between the fourth dichroic mirror 405 and the seventh aperture 410; and the second light source scattering measurement channel 432 adds a thirteenth lens 426 between the fifth reflector 406 and the eighth aperture 411.

[0036] Figure 3a-3c FIG. 1 is a schematic diagram of wafer scanning imaging performed by a motion platform according to an embodiment of the present invention. Figure 3a As shown, the motion platform is configured to perform wafer scanning imaging in a spiral manner. Figure 3b As shown, the motion platform is configured to perform wafer scanning imaging in a circular plus stepping manner. Figure 3c As shown, the motion platform is configured to perform wafer scanning and imaging in an XY back-and-forth linear manner. In one embodiment of the present invention, according to the size of the wafer to be inspected and the purpose of inspection, before scanning, the controller sets the step of the scanning trajectory and the scanning range, and the motion platform completes the relevant scanning according to the settings of the controller. The wafer scanning and imaging method is not limited to Figure 3a-3c The scanning method shown may also be used in other scanning methods, which will not be described in detail here.

[0037] The first laser 101 includes but is not limited to semiconductor lasers, solid lasers and gas lasers, continuous lasers, and pulsed lasers. The laser wavelength of the first laser 101 can be set to an ultraviolet wavelength or a visible light wavelength, which is not the only limitation here. In one embodiment of the present invention, the laser wavelength of the first laser 101 is preferably 405nm. The first lens 102, the first aperture 103 and the second lens 104 constitute a first laser beam expansion system 105. The lens and aperture in the first laser beam expansion system 105 expand and spatially filter the light beam. The laser energy density after beam expansion is reduced, which reduces the energy damage threshold requirement for the wave plate selection. The light beam emitted from the first laser beam expansion system 105 passes through the first half wave plate 106, and the first half wave plate 106 rotates according to the detection needs, so that the polarization direction of the inclined incident light beam 109 is switched (such as P, S, Q polarization). The first reflector 107 transmits the oblique incident light beam 109 to the third lens 108, and the oblique incident light beam 109 is focused by the third lens 108 and incident on the upper surface 5011 of the wafer 501 along the first direction at the focus 110. The oblique incident light beam 109 is incident at an angle of ≥55 degrees to the direction perpendicular to the surface of the wafer.

[0038] Figure 1 In the embodiment, the oblique incident light beam 109 is mirror-reflected on the upper surface 5011 of the wafer 501 , the oblique reflected light beam 209 is focused by the fourth lens 201 , and the second reflector 202 transmits the oblique reflected light beam 209 to the second aperture 203 . Figure 2, the inclined reflected light beam 209 is focused by the fifth lens 210 and then transmitted to the second aperture 203. The neutral density filter 204, the quarter wave plate 205, and the Wollaston prism 206 form a reflective modulator 211. After being modulated by the reflective modulator 211, the inclined reflected light beam 209 is diverged to the first quadrant detector 207 and the second quadrant detector 208 for energy detection and position measurement. The reflective modulator 211 may also include other polarization beam splitting prisms. The Wollaston prism 206 or other polarization beam splitting prisms separate the inclined reflected light beam 209 into two polarized lights (P polarized light and S polarized light), which finally reach the first quadrant detector 207 and the second quadrant detector 208. The reflected light beam after passing through the second aperture 203 diverges, and the spot size diverged to the first quadrant detector 207 and the second quadrant detector 208 is about 1 / 2 of the diameter of the photosensitive surface of the first quadrant detector 207 and the second quadrant detector 208. The four-quadrant detector determines the direction and intensity of the incident light by comparing the output signals of the four quadrants. Each quadrant has a photodiode that can independently measure the light intensity of each quadrant. By comparing the light intensity of the four quadrants, the deflection angle and position of the light beam can be determined, thereby achieving the measurement of the longitudinal position and warpage of the wafer. The aperture in the reflection detection channel is used to block the interference of the bottom reflected light and improve the signal-to-noise ratio of the defect detection of the reflection detection channel.

[0039] The surface morphology of the wafer can be detected by combining the first light source channel and the reflection detection channel. The first half wave plate 106 is adjusted so that the oblique incident light beam 109 is incident on the upper surface 5011 of the wafer 501 with P / S polarization. After the light beam is reflected from the upper surface 5011 of the wafer 501, the linearly polarized reflected light is converted into circularly polarized light by the quarter wave plate 205. The light emitted from the quarter wave plate 205 is split into P and S polarized light after passing through a Wollaston prism or other polarization beam splitting prism, and is respectively emitted to the first four-quadrant detector 207 and the second four-quadrant detector 208, wherein one PSD is used for surface morphology measurement. Figure 4 As shown in the figure, the four-quadrant detector is a photoelectric detection device formed by arranging four photodiodes with exactly the same performance according to the requirements of rectangular coordinates. The center of the detector is the intersection point produced by the cross-shaped separation. The laser irradiates the center of the detector and generates equal current or voltage signals in each part of the detector. The four photosensitive areas of the four-quadrant detector are set as A, B, C, D, V A 、V B 、V C 、V D The voltage values ​​measured for the four photosensitive areas. Figure 5 As shown, if the upper surface 5011 of the wafer 501 has a slight surface morphology change, the reflected light will deviate from the initial direction, so the position of the reflected laser spot changes. Figure 6The figure shows the position change of the laser spot on the four-quadrant detector caused by the circumferential or radial surface change of the wafer. The position of the laser spot is converted into different current or voltage signal changes on each detector. Define the radial surface topography Z R =(V A +V B )-(V C +V D ), circumferential surface topography Z C =(V A +V C )-(V B +V D ). By processing these signal data, the position change of the laser spot center caused by the change of the wafer surface morphology can be calculated, thereby realizing the detection of the wafer surface morphology. Figure 7 As shown, the system obtains the surface topography of the wafer and the slope change of the defective cross section through detection and data processing. It should be noted that when the wafer surface topography is detected, the translation stage 602 does not respond and remains fixed.

[0040] However, according to the Rayleigh criterion, the smaller the laser focus spot, the smaller its focal depth range. Defocusing will cause the illumination spot to diffuse, the energy density to decrease, and affect the scattered and reflected signal energy, thereby reducing the accuracy of the wafer defect detection equipment. In the actual scanning process, there is a certain height difference on the surface of the wafer itself, and the motion mechanism, wafer adsorption device, etc. will introduce additional height changes, causing the wafer to defocus. Therefore, the accuracy of defect measurement can be significantly improved by real-time focus tracking or defocus compensation of the data through the translation stage 602. Figure 8 FIG. 1 is a schematic diagram of the defocus correction principle of an embodiment of the present invention. Figure 8 As shown, the first light source channel incidents the oblique incident light beam 109 onto the wafer 501, and the oblique reflected light beam 209 enters the reflection measurement channel. Because there is a certain height difference between the wafer and the optimal focusing plane, the defocus amount is ΔZ. After the reflected light enters the reflection detection channel, the displacement amount generated on the four-quadrant detector is ΔX, and the precise value of ΔX is analyzed by the four-quadrant detector signal. The wafer detection system provided by the present invention calculates the displacement ΔX in real time, calculates the defocus amount ΔZ according to the displacement ΔX, adjusts the displacement stage 602 according to the defocus amount ΔZ, completes real-time tracking, and realizes defocus compensation. When the defocus amount of the detected wafer is ΔZ, the displacement Δx' generated on the object plane of the reflection modulation component is Δx'=2ΔZsinθ, where θ is the angle between the laser light source and the normal. Assuming that the magnification of the reflection modulation component is α, the position offset ΔX caused by the defocus amount ΔZ of the detected wafer on the four-quadrant detector is ΔX=2αΔZsinθ. The precise value of ΔX is analyzed by four-quadrant detector signals to achieve real-time measurement of the defocus amount.

[0041] By combining the first light source channel and the reflection detection channel, it is possible to detect whether there is film contamination on the surface of the wafer. The first half wave plate 106 is adjusted so that the oblique incident light beam 109 is incident on the upper surface 5011 of the wafer 501 with Q polarization. Figure 9a As shown, Q polarized light is projected onto the upper surface 5011 of the wafer 501 at a certain incident angle. After being reflected and refracted by the thin film 502, it is generally still polarized light. However, because there is a thin film 502 on the upper surface 5011 of the wafer 501, the upper and lower surfaces of the thin film respectively reflect different polarized light (i.e., S polarization and P polarization). There is an optical path difference between the S polarized light and the P polarized light reflected from the upper and lower surfaces. Therefore, there is a phase difference between the S polarized reflected light and the P polarized reflected light. The S polarized reflected light and the P polarized reflected light pass through the quarter wave plate 205, the Wollaston prism 206 or other polarization beam splitting prism. The Wollaston prism 206 or other polarization beam splitting prism separates the S polarized reflected light and the P polarized reflected light, and projects them onto the first four-quadrant detector 207 and the second four-quadrant detector 208, respectively. Because there is a phase difference between the S polarized reflected light and the P polarized reflected light, the energy on the first four-quadrant detector 207 and the second four-quadrant detector 208 is not equal. As shown in FIG. Figure 9b As shown, assuming that the voltage value corresponding to the energy on the first four-quadrant detector 207 is SP1, and the voltage value corresponding to the energy on the second four-quadrant detector 208 is SP2, by calculating the difference between SP2 and SP1, it can be confirmed whether there is film contamination on the detection wafer. If there is no film on the upper surface 5011 of the wafer 501, the separated S polarized light and P polarized light have equal energy. Therefore, the voltage value SP1 corresponding to the energy on the first four-quadrant photodetector 207 is equal to the voltage value SP2 corresponding to the energy on the second four-quadrant photodetector 208, that is, SP2-SP1=0. If there is a film 502 on the upper surface 5011 of the wafer 501, the separated S polarized light and P polarized light have unequal energy. Therefore, the voltage value SP1 corresponding to the energy on the first four-quadrant photodetector 207 is unequal to the voltage value SP2 corresponding to the energy on the second four-quadrant photodetector 208, that is, SP2-SP1≠0. Therefore, by determining whether the value of SP2 - SP1 is zero, it is possible to confirm whether there is thin film contamination on the upper surface 5011 of the wafer 501 .

[0042] The second laser 301 emits a second light source to the optical isolator 302. The optical isolator 302 is a one-way light-transmitting magneto-optical device that protects upstream optical components from back reflection. Back reflection can cause a series of unstable factors to the light source, including intensity noise, frequency offset, mode hopping and mode-locking failure mode jump. More seriously, high-intensity back reflection may permanently damage optical components. The second light source beam passes downward through the second half-wave plate 303, then through the polarization beam splitter 304, and then is emitted to the DIC prism 305. The DIC prism 305 is composed of two prisms 305A and 305B of birefringent materials. The two prisms can be formed of materials such as calcite, and the two prisms can be fixed or bonded together. The optical axis of prism 305A is perpendicular to the optical axis of prism 305B, and both optical axes are perpendicular to the propagation direction of the second light source beam 313. The function of the DIC prism 305 is to divide the incoming linear polarized light beam into two independent orthogonal linear polarized light beams 313A and 313B, which deviate from each other by a small angle. Then, the two light beams are expanded by the second laser beam expansion system 309 (the second laser beam expansion system 309 includes the sixth lens 306, the third aperture 307, and the seventh lens 308), and then the second light source beam 313 is focused by the eighth lens 310 to fix the required spot size on the upper surface 5011 of the wafer 501. The focused light beam is reflected by the third reflector 311 and the fourth reflector 312, and is incident on the upper surface 5011 of the wafer 501 along the second direction at the focus 110. The second light source beam, i.e., the vertical incident light beam 313, is incident at an angle perpendicular to the surface of the wafer. It is directed to the upper surface 5011 of the wafer 501. The second laser 301 includes but is not limited to semiconductor lasers, solid lasers, gas lasers, continuous lasers, and pulsed lasers. The laser wavelength of the second laser 301 can be set to an ultraviolet wavelength or a visible light wavelength, which is not limited here. In one embodiment of the present invention, the laser wavelength of the second laser 301 is preferably 355 nm. The second light source provides a vertical illumination light source for wafer detection and excites a photoluminescence signal of the wafer.

[0043] Traditional surface topography measurement can solve problems such as bending / warping, part flatness or thickness variation, and polishing indentation by evaluating relatively large height errors and relatively large lateral dimensions, but such tools cannot detect small height differences and small diameter defects. The vertical detection channel provided by the present invention can detect small height differences and small diameter defects. Fig.10As shown, the DIC prism 305 divides the incoming linear polarized light beam into two independent orthogonal polarized light beams 313A and 313B, which are offset from each other by a small angle. Because the orthogonal polarized light beams 313A and 313B are offset from each other by a small angle, the light beams are focused by the eighth lens 310 to form two offset focal points that are projected onto the upper surface 5011 of the wafer 501. When and only when the upper surface 5011 of the wafer 501 is perpendicular to the light beams 313A and 313B, the reflected light beam with ideal optical alignment will return along the same path as the incident light beam. It is reflected back through the elements shown in the figure, and is reflected to the fourth reflector 312, the third reflector 311, the eighth lens 310, the second laser beam expansion system 309, and the DIC prism 305. The DIC prism 305 collects the reflected parts of the two orthogonal linear polarized light beams 313A and 313B, merges the two reflected parts into one light beam, and directs the light beam to the array detector 314. Fig.11 This is a schematic diagram of the position of the light spot in the array detector of an embodiment of the present invention. The array detector 314 is preferably a multi-element detector array, but sensors such as CCD can also be used. Any local surface irregularity of the wafer will cause the peak position of the reflected light beam to deviate from the path of the array detector 314 to different diodes. The signal from each detector is weighted with a weight proportional to the relative position of the light beam, and the signals from all detectors are added, and the signal is normalized using the total light power detected to obtain a linear voltage proportional to the position of the light beam, regardless of the absolute light power level. The wafer defect detection system measures the sum of the diode signals, calculates the slight change information of the wafer surface based on the reflected signal, and records the upper (x, y) or (r, θ) position information of the wafer 501, and generates a wafer topography map based on the slight change information and position information.

[0044] The smooth surface of an ideal optical element will only produce reflected light in the reflection direction, while defects will cause a sudden change in the surface refractive index of the optical element, modulating the amplitude and phase of the incident light, and thus causing scattered light in all directions in space. The presence and size of defects can be judged based on the intensity of scattered light. Figure 12a-12h FIG. 1 is a schematic diagram of light beam scattering on a wafer surface according to an embodiment of the present invention. Fig.12a This is the case where the light beam is incident vertically on the wafer surface. The light beam is incident vertically and reflected vertically. Figure 12b , 12c 12d and 12d respectively represent the cases where the light beam is vertically incident on the wafer surface with particles, pits, and protrusions. Due to the presence of particles, pits, or protrusions on the wafer surface, the scattered light beam has multiple emission directions. Fig.12e In the case where the light beam is incident on the wafer surface at an angle, the light beam is reflected in one direction. Fig.12f , 12g12h and 12h respectively represent the cases where the light beam is obliquely incident on the wafer surface with particles, pits, and protrusions. Due to the presence of particles, pits, or protrusions on the wafer surface, the scattered light beam has multiple emission directions.

[0045] Figure 13a-13b Schematic diagram of a reflective objective lens collecting scattered light from a wafer according to an embodiment of the present invention. The reflective objective lens 401 collects scattered light from the upper surface 5011 of the wafer 501 and the photoluminescence signal stimulated by the incident light. The reflective objective lens can collect more light energy, especially scattered light at low angles, and has higher detection sensitivity. The reflective objective lens has no chromatic aberration and has higher imaging quality. Fig.13a For the case of finite distance conjugation, it corresponds to Figure 1 The embodiment shown. Fig.13b For the case of infinite conjugation, it corresponds to Figure 2 The embodiment shown.

[0046] The scattered light beam includes scattering by the first light source, scattering by the second light source, and photoluminescence scattering. The scattering by the first light source is the scattering caused by the oblique incident light source beam, and the laser wavelength of the first light source is preferably 405nm. The scattering by the second light source is the scattering caused by the vertical incident light source beam, and the laser wavelength of the second light source is preferably 355nm. Photoluminescence scattering includes VIS-PL scattering, NUV-PL scattering, and NIR-PL scattering. The scattering detection channel includes five scattering measurement channels, namely, the first light source scattering measurement channel, the second light source scattering measurement channel, the VIS-PL scattering measurement channel, the NUV-PL scattering measurement channel, and the NIR-PL scattering measurement channel. Figure 2 In the illustrated embodiment, each scattering measurement channel includes a dichroic mirror or a reflector, a lens, an aperture, a filter, and a PMT. The reflective objective lens 401 collects the scattered light from the upper surface 5011 of the wafer 501 and the photoluminescence signal excited by the incident light, and separates the defect signals at different wavelengths through the first dichroic mirror 402, the second dichroic mirror 403, the third dichroic mirror 404, the fourth dichroic mirror 405, and the fifth reflector 406, and enters five different scattering measurement channels. The lens in the scattering measurement channel is used to match the infinite conjugate reflective objective lens 401 so that the light beam is focused on the rear aperture. The aperture in the scattering measurement channel is used to block the interference of the bottom reflected light and improve the signal-to-noise ratio of defect detection in the scattering measurement channel. The filter in the scattering measurement channel is used to further selectively filter the required scattering band to improve the signal-to-noise ratio of defect detection.

[0047] In one embodiment of the present invention, Figure 2As shown, the first dichroic mirror 402 reflects light waves with wavelengths higher than 800nm, namely the infrared band, and transmits light waves with wavelengths lower than 800nm. The light waves with wavelengths higher than 800nm ​​pass through the ninth lens 422, are focused on the fourth aperture 407, and then pass through the first filter 412, namely the near-infrared filter, to be irradiated on the photosensitive surface of the first PMT417; the second dichroic beam splitter 403 reflects light waves with wavelengths between 420nm and 800nm, namely the visible light band, and transmits light waves with wavelengths lower than 420nm. The light waves with wavelengths between 420nm and 800nm ​​pass through the tenth lens 423, are focused on the fifth aperture 408, and then pass through the second filter 413, namely the visible light filter, to be irradiated on the photosensitive surface of the second PMT418; the third dichroic beam splitter 404 reflects light waves with wavelengths between 400nm and 420nm, namely the first light source band, and transmits light waves with wavelengths lower than 400nm. The light waves with wavelengths between 400nm and 420nm pass through the eleventh lens 424, are focused on the sixth aperture 409, and then pass through the third filter 414 to irradiate the photosensitive surface of the third PMT419; the fourth dichroic beam splitter 405 reflects the light waves with wavelengths between 360nm and 400nm, i.e., the near-ultraviolet band, and transmits the light waves with wavelengths lower than 360nm; the light waves with wavelengths between 360nm and 400nm pass through the twelfth lens 425, are focused on the seventh aperture 410, and then pass through the fourth filter 415 to irradiate the photosensitive surface of the fourth PMT420; the fifth reflector 406 reflects the light waves with wavelengths lower than 360nm, i.e., the second light source band; the light waves with wavelengths lower than 360nm pass through the thirteenth lens 426, are focused on the eighth aperture 411, and then pass through the fifth filter 416, i.e., the near-ultraviolet filter, to irradiate the photosensitive surface of the fifth PMT421.

[0048] During the wafer scanning process, the laser irradiates different positions of the wafer, and the PMT outputs different signals according to the changes in the detection beam fed back from the scanning position, and detects one or more scattered light defects based on the characteristics measured by at least one of the five scattering measurement channels. PMT is an optical detection device with extremely high sensitivity and ultrafast time response, and is an optical device that can detect weak optical signals. It can be understood that in practical applications, the selection method of the optical signal sensor is diverse, and it is necessary to select a suitable optical detection device according to the actual application situation, which is not the only limitation here. Photomultiplier tubes can be used to measure light intensity. In one embodiment of the present invention, the five scattering measurement channels can be configured with a spectrometer, which is used to measure the spectrum of the scattering measurement channel band; or a spectrometer is set between the five scattering measurement channels and the reflective objective lens, and the spectrometer is used to measure the overall spectrum of the reflected light beam.

[0049] One or more characteristics of at least one of the first light source scattering, the second light source scattering, the VIS-PL scattering, the NUV-PL scattering, and the NIR-PL scattering are measured. One or more scattering defects are detected based on the one or more characteristics; one or more photoluminescence defects are detected based on the one or more characteristics. Fig.14 The middle curve is a set of photoluminescence intensity versus wavelength curves for the region without photoluminescence defects in the wafer, corresponding to Fig.15 When excited with UV light, wafers containing various types of photoluminescent defects (such as stacking faults or basal plane defects) can produce Fig.15 In one embodiment of the present invention, when excited by a 325 nm laser, the stripe stack may show a peak at about 420 nm, i.e. Fig.15 Curve a in the figure; when excited by a 325nm laser, the 2S type stacking fault can show a peak at about 500nm, that is, Fig.15 Curve b in the figure; when excited by a 325nm laser, the 4S type stacking fault can show a peak at about 460nm, that is, Fig.15 It should be noted that although Fig.15 The spectra depicted in FIG. 1 were acquired using a 325 nm UV laser, but the same spectrum is also observed in spectra produced using lasers of wavelengths other than 325 nm (e.g., but not limited to, a 355 nm laser). Fig.15 The spectrum graph shown in . The present invention can independently measure selected spectral bands of the photoluminescence spectrum associated with a given wafer, and detect and / or classify the photoluminescence defects formed based on the measurement. For example, as described above, the types of stacking faults in the sample are classified. The first light source scattering and the second light source scattering carry information about particles, pits or protrusions on the surface of the wafer. Through the collection of the reflective objective lens, the detection of the PMT, and the processing of the controller and the computer, a scattering defect map of the wafer can be generated. The scattering defects are mainly surface morphology defects, such as common particles, scratches, cracks, stains, pits, protrusions and other defects.

[0050] The wafer defect detection system provided by the present invention can also be applied to the detection of translucent or transparent wafers. Translucent or transparent wafers represented by silicon carbide are usually polished only on one side and are usually used for power devices in automobiles and other applications. In such wafers, the upper active surface is polished, while the lower passive surface is not polished. If the wafer is inspected using traditional methods, it is difficult to detect the polished upper surface. The emitted laser beam will penetrate the transparent wafer and illuminate the unpolished lower surface. The scattered and reflected signals from the unpolished lower surface usually overwhelm the signals from the defects on the upper surface. Therefore, it is difficult to detect any defects that may exist on the upper surface of the wafer. When the first laser projects the oblique incident light beam 109 obliquely onto the surface of the wafer 501, if the wafer 501 is made of a transparent or translucent material, the incident laser beam is reflected and refracted by the upper surface 5011 of the wafer 501, and the refracted light beam is projected onto the lower surface 5012 of the wafer 501, and is reflected back to the upper surface 5011, and is emitted after being refracted by the upper surface 5011, thereby entering the reflection detection channel, such as Fig.16 When the first laser projects the oblique incident light beam 109 obliquely onto the surface of the wafer 501, if the wafer 501 is made of a transparent or semi-transparent material, the incident laser beam is reflected and refracted by the upper surface 5011 of the wafer 501, and the refracted light beam is projected onto the lower surface 5012 of the wafer 501 and is scattered on the lower surface 5012, thereby entering the scattering detection channel, as shown in FIG. Fig.17 shown. Fig.16 and Fig.17 111 in the figure is the focus of the refracted light beam on the lower surface 5012 of the wafer 501. Due to the interference of the reflected light and scattered light on the lower surface 5012 of the wafer 501, the signal-to-noise ratio of the defect detection on the upper surface 5011 of the wafer 501 is reduced, and the upper surface 5011 of the wafer 501 cannot be effectively detected. Therefore, an aperture is set at the focus point of the inclined reflected light beam 209 and the scattered light beam 427 to block the interference of the reflected light and scattered light on the lower surface 5012 of the wafer 501, thereby improving the defect detection signal-to-noise ratio of the reflection detection channel and the scattered detection channel, and broadening the application scenarios of the wafer defect detection system.

[0051] Based on the wafer defect detection system described above, the present invention also provides a wafer defect detection method. Fig.18 The figure is a schematic flow chart of a wafer defect detection method according to an embodiment of the present invention.

[0052] First, a light beam from a first light source is directed onto the surface of the wafer along a first direction, wherein the first direction is a direction inclined relative to the surface of the wafer, and the angle of the inclined incidence is ≥55 degrees from the direction perpendicular to the surface of the wafer.

[0053] Next, the light beam of the second light source is directed onto the surface of the wafer along a second direction, wherein the second direction is a direction nearly perpendicular to the surface of the wafer, and the angle of incidence is perpendicular to the surface of the wafer.

[0054] Next, collect the tilted reflected light beam from the wafer, measure the energy of the tilted reflected light beam through the four-quadrant detector to determine the defects on the wafer, determine the topography on the wafer or correct the height change of the wafer by irradiating the laser spot on the position of the four-quadrant detection, and determine the film contamination on the wafer by measuring the energy on different four-quadrant photodetectors. Specifically, the film contamination on the wafer is determined by calculating the difference in voltage values ​​corresponding to the energy on different four-quadrant photodetectors.

[0055] Next, the vertical reflected beam from the wafer is collected and passed through an array detector to detect small height differences and small diameter defects.

[0056] Next, the scattering from the wafer is collected, and the scattering includes at least one of elastic scattering caused by one or more defects of the wafer or photoluminescence scattering emitted by one or more photoluminescence defects of the wafer. In one embodiment of the present invention, the light beam of the second light source incident along the second direction is suitable for causing one or more photoluminescence defects of the sample to emit photoluminescence light. The scattering from the wafer, that is, the light beam of the first light source and the light beam of the second light source are incident on the wafer and cause scattering and photoluminescence light beams to be collected by the reflective objective lens, and then enter five scattering measurement channels after being split by a dichroic mirror or a reflective mirror.

[0057] Next, the scattering from the wafer is separated into a first light source band, a second light source band, a visible light band, a near ultraviolet band, and a near infrared band. The light beams of the first light source band, the second light source band, the visible light band, the near ultraviolet band, and the near infrared band are separated by dichroic mirrors, reflectors, and filters of the five scattering measurement channels.

[0058] Next, one or more characteristics of at least one of the first light source band, the second light source band, the visible light band, the near ultraviolet band, and the near infrared band are measured. The light beams of the first light source band, the second light source band, the visible light band, the near ultraviolet band, and the near infrared band separated by the dichroic mirrors, reflectors, and filters of the five scattering measurement channels are respectively irradiated on the photosensitive surfaces of the five photomultiplier tubes to detect the size of the light beam energy. In one embodiment of the present invention, the spectral characteristics of the radiation from the wafer can also be measured, and the spectral components in the light beam can be measured using a spectrometer.

[0059] Next, one or more scattering defects are detected based on the one or more characteristics. One or more scattering defects are detected by comparing and analyzing the beam energies of the first light source band, the second light source band, the visible light band, the near ultraviolet band, and the near infrared band.

[0060] Next, one or more photoluminescence defects are detected based on the one or more characteristics. One or more photoluminescence defects are detected based on the light beam spectral components measured by the spectrometer and the analysis of the light beam energies of the first light source band, the second light source band, the visible light band, the near ultraviolet band, and the near infrared band.

[0061] The present invention can also control the motion platform to scan the wafer to be inspected through a controller, and form a defect distribution map based on the defect information and scanning coordinate information corresponding to each scanning position. Specifically, the detection information data set corresponding to each stored scanning position is sorted, and the scanning coordinate information corresponding to each detection information data set is arranged. After the arrangement is completed, a defect distribution map corresponding to the wafer to be inspected is formed, which improves the accuracy and intuitiveness of the wafer defect position marking. Furthermore, the growth of the wafer substrate in the defect distribution area is determined based on the spectral characteristics detected by the spectrometer, the defects are identified and accurately classified, the source and evolution of the defects are traced, and the corresponding data support is provided for the improvement of the wafer process technology.

[0062] Although various embodiments of the present invention are described above, it should be understood that they are presented as examples only and not as limitations. It is obvious to those skilled in the relevant art that various combinations, modifications and changes can be made thereto without departing from the spirit and scope of the present invention. Therefore, the breadth and scope of the present invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should only be defined according to the attached claims and their equivalents.

Claims

1. A wafer defect detection system, characterized in that: include: A first light source channel, a second light source channel, a reflection detection channel, a vertical detection channel, a scattering detection channel, and a motion platform; The first light source channel includes a first laser and a first light source modulation component, and the first laser emits a first light source; The second light source channel includes a second laser and a second light source modulation component, and the second laser emits a second light source; The reflection detection channel includes a reflection modulation component and a four-quadrant detector, and the reflection detection channel is configured to collect the inclined reflection light beam of the wafer, and the inclined reflection light beam is incident on the four-quadrant detector after being modulated by the reflection modulation component; The vertical detection channel includes an array detector, and the vertical detection channel is configured to collect a vertical reflected light beam of the wafer, and the vertical reflected light beam is incident on the array detector after being modulated by a second light source modulation component; The scattering detection channel includes a reflective objective lens and a scattering measurement channel, wherein the reflective objective lens is configured to collect a scattered light beam of the wafer, and the scattered light beam is focused and incident on the scattering measurement channel after passing through the reflective objective lens; The motion platform is configured to secure a wafer and selectively actuate the wafer so as to perform a scanning process using the first light source and the second light source.

2. The wafer defect detection system according to claim 1, characterized in that: The wafer defect detection system also includes a controller, which is configured to control the movement of the motion platform, process the signals obtained by the array detector, the four-quadrant detector and the scattering measurement channel and transmit the signals to a computer to generate an image of the wafer. The output ends of the array detector, the four-quadrant detector and the scattering measurement channel are connected to the input end of the controller, and the output end of the controller is externally connected to the computer.

3. The wafer defect detection system according to claim 1, characterized in that: The first light source modulation assembly includes a lens, a reflector, an aperture and a half wave plate; After being modulated by the first light source modulation component, the first light source is focused along a first direction and obliquely incident onto the surface of the wafer, and the angle of the oblique incidence is ≥55 degrees to the direction perpendicular to the surface of the wafer.

4. The wafer defect detection system according to claim 1, characterized in that: The second light source modulation assembly includes an optical isolator, an aperture, a lens, a reflector, a polarization beam splitter, a DIC prism and a half wave plate; The DIC prism is used to split the incoming linearly polarized light beam into two independent orthogonal polarized light beams; After being modulated by the second light source modulation component, the second light source is focused along a second direction and incident on the surface of the wafer, and the angle of incidence is perpendicular to the surface of the wafer.

5. The wafer defect detection system according to claim 1, characterized in that: The reflective modulation assembly includes a lens, a reflector, an aperture, a neutral density filter, a quarter wave plate and a Wollaston prism; The four-quadrant detector is used to measure the energy of the inclined reflected light beam and the position where the laser spot is irradiated on the four-quadrant detection, and the position where the laser spot is irradiated on the four-quadrant detection is used to measure the changes caused by the change of the wafer surface morphology; The thin film contamination on the wafer is determined by measuring the energy on different four-quadrant photodetectors.

6. The wafer defect detection system according to claim 1, characterized in that: The scattered light beam includes first light source scattering, second light source scattering, and photoluminescence scattering; The photoluminescence scattering includes visible light-photoluminescence scattering, near ultraviolet-photoluminescence scattering and near infrared-photoluminescence scattering; The scattering measurement channels include a first light source scattering measurement channel, a second light source scattering measurement channel, a visible light-photoluminescence scattering measurement channel, a near ultraviolet-photoluminescence scattering measurement channel, and a near infrared-photoluminescence scattering measurement channel; The first light source scattering measurement channel includes a dichroic mirror, an aperture, a filter and a photomultiplier tube; The second light source scattering measurement channel includes a reflector, an aperture, a filter and a photomultiplier tube; The visible light-photoluminescence scattering measurement channel includes a dichroic mirror, an aperture, a filter and a photomultiplier tube; The near-ultraviolet-photoluminescence scattering measurement channel includes a dichroic mirror, an aperture, a filter, and a photomultiplier tube; The near-infrared-photoluminescence scattering measurement channel includes a dichroic mirror, an aperture, a filter, and a photomultiplier tube; detecting one or more scattering defects based on the characteristics measured by at least one of the five scattering measurement channels; One or more photoluminescent defects are detected based on the characteristics measured by at least one of the five scattering measurement channels.

7. The wafer defect detection system according to claim 1, characterized in that: The motion platform includes a rotating platform and a translation platform; The motion platform is configured to scan in a spiral mode, or to scan in a circular plus stepping mode, or in an XY scanning mode.

8. A wafer defect detection method, characterized in that: Used to control the wafer defect detection system as described in any one of claims 1 to 7 to detect the wafer to be detected, comprising: directing a light beam from a first light source onto a surface of the wafer along a first direction; directing a light beam from a second light source onto the surface of the wafer along a second direction; Collecting the tilted reflected light beam from the wafer, measuring the energy of the tilted reflected light beam through a four-quadrant detector to determine the defects on the wafer, determining the topography on the wafer or correcting the height change of the wafer by irradiating the laser spot on the position of the four-quadrant detection, and determining the film contamination on the wafer by measuring the energy on different four-quadrant photoelectric detectors; Collect vertical reflected beams from the wafer and detect small height differences and small diameter defects through array detectors; collecting scatter from a wafer, the scatter comprising at least one of elastic scatter caused by one or more defects of the wafer or photoluminescent scatter emitted by one or more photoluminescent defects of the wafer; Separating the scattering from the wafer into a first light source band, a second light source band, a visible light band, a near ultraviolet band, and a near infrared band; measuring one or more characteristics of at least one of the first light source band, the second light source band, the visible light band, the near ultraviolet band, and the near infrared band; detecting one or more scattering defects based on the one or more characteristics; One or more photoluminescent defects are detected based on the one or more characteristics.

9. The wafer defect detection method according to claim 8, characterized in that: The film contamination on the wafer is determined by calculating the difference in voltage values ​​corresponding to the energy on different four-quadrant photodetectors.

10. The wafer defect detection method according to claim 8, characterized in that: Scan the wafer to be inspected, and form a defect distribution map based on the defect information corresponding to each scanning position and the scanning coordinate information.

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