Wafer and chip defect detection system and method based on linear array brillouin microscopy

Abstract

This invention discloses a wafer and chip defect detection system and method based on linear array Brillouin microscopy, belonging to the fields of optical precision measurement and wafer inspection. The system connects a Brillouin scattering detection module, a bright-field detection module, and a signal processing and feedback module; the signal processing and feedback module is connected to a displacement module; the signal processing and feedback module is also connected to an imaging and analysis module, transmitting single-shot linear beam measurement data to the imaging and analysis module; the displacement module is connected to the sample; and the Brillouin scattering detection module and bright-field detection module are connected to the sample to acquire sample information. This invention enables line-scan confocal measurement of the mechanical properties of wafers and non-transparent chips using the Brillouin scattering detection module, significantly improving the speed of Brillouin scattering detection; the combination of bright-field linear array detection and Brillouin scattering linear array detection allows for the simultaneous acquisition of geometric and mechanical stress defects in wafer and chip samples, broadening the range of defect detection parameters.

Description

Technical Field

[0001] This invention belongs to the fields of optical precision measurement and wafer inspection, and mainly relates to a wafer and chip defect detection system and method based on linear array Brillouin microscopy. Background Technology

[0002] Defect detection of wafers and chips is a key step in chip manufacturing. With the development of chip manufacturing technology, it is not only required to record defects such as surface scratches, particles, and grooves, but also to measure their mechanical properties, chemical composition, and crystal structure defects.

[0003] Traditional wafer defect detection methods are based on bright-field illumination or dark-field photoexcitation illumination to detect defects on the wafer surface or subsurface. For example, Chinese invention patent documents with publication numbers CN112505064A and CN114441440A disclose a wafer defect detection method for faceted regions, which realizes simultaneous and rapid detection of bright-field linear arrays and dark-field arrays, but the detection range is limited to geometric defects.

[0004] Brillouin scattering microscopy, as an emerging microscopic method, can detect the mechanical properties and stress distribution of wafers and chips, thereby revealing more information about their performance and defects. For example, Chinese invention patent document CN113916891A discloses a microscopic system that combines bright-field confocal and dark-field confocal Brillouin detection. It effectively separates the surface reflection signal and subsurface scattering signal of the sample by using an optical fiber to generate a ring illumination beam and complementary aperture blocking detection, thus achieving three-dimensional detection of sample defects and mechanical properties. However, this method can only perform point scan detection of the sample, limiting the imaging speed. The paper Scientific Reports 6:35398 proposes a line-scanning Brillouin microscope. The incident objective focuses a laser beam into the sample to form a line beam, and the acquisition objective is at a 90-degree angle to the incident objective to acquire the line beam. Then, a high-resolution two-dimensional Brillouin image is obtained through demodulation using a virtual imaging phase array, reducing the acquisition time by two orders of magnitude compared to the point-scanning Brillouin microscope. However, this method is a transmission-type structure, which can only measure transparent samples and cannot detect turbid or opaque samples.

[0005] Currently, no existing technology can achieve linear array detection of Brillouin microscopy and combine it with bright-field linear array detection to realize defect detection on wafers and non-transparent chips. This invention discloses a wafer and chip defect detection system and method based on linear array Brillouin microscopy. While rapidly acquiring geometric defects on the surface of wafers and chips using bright-field confocal microscopy, it can also detect the mechanical properties of the sample surface through Brillouin microscopy, thus integrating the detection of both geometric and mechanical stress defects. This technology utilizes linear array confocal microscopy to achieve both bright-field and Brillouin microscopy detection, improving imaging speed and effectively filling the aforementioned needs. Summary of the Invention

[0006] The purpose of this invention is to solve the problem that existing defect detection technologies cannot simultaneously and rapidly detect geometric defects and mechanoacoustic properties of samples using a linear array, and to provide a linear array defect detection system that combines bright-field detection and Brillouin detection. This system has the advantages of fast detection speed and the ability to simultaneously detect geometric defects and mechanoacoustic properties of samples.

[0007] The specific technical solution adopted in this invention is as follows:

[0008] In a first aspect, the present invention provides a wafer and chip defect detection system based on linear array Brillouin microscopy, including a Brillouin scattering detection module, a bright field detection module, a displacement module, a signal processing and feedback module, and an imaging and analysis module;

[0009] The sample is placed on the displacement module, and the signal processing and feedback module can control the movement of the sample through the displacement module. The Brillouin scattering detection module is used to detect the Brillouin spectrum information of the sample surface, thereby obtaining its mechanical stress defect distribution information. The bright field detection module is used to detect the bright field light intensity information of the sample surface, thereby obtaining its geometric defect distribution information. The signal processing and feedback module is connected to the Brillouin scattering detection module and the bright field detection module respectively, and is used to receive the collected detection signals and process them into single-beam measurement data. The imaging and analysis module is connected to the signal processing and feedback module, and is used to receive, store, and image process the single-beam measurement data, while feeding back the results to the signal processing and feedback module.

[0010] Preferably, the sample is a wafer or a chip.

[0011] Preferably, the Brillouin scattering detection module includes a Brillouin scattering linear array light source assembly, a third filter, a second polarizing beam splitter, a second quarter-wave plate, a dichroic mirror, an objective lens, a reflecting mirror, a filter assembly, a second cylindrical mirror, a virtual imaging phase array, a third cylindrical mirror, an adjustable slit, a converging lens, and an area array camera that together constitute the optical system.

[0012] The parallel polarized beam output by the Brillouin scattering linear array light source component can be converged into a linear beam after passing through the third filter, the second polarizing beam splitter, the second quarter-wave plate, the dichroic mirror, and the objective lens in sequence, and then irradiate the sample surface. The beam formed by reflection from the sample surface can be converged into a linear beam after passing through the objective lens, the dichroic mirror, the second quarter-wave plate, the second polarizing beam splitter, the reflector, the filter component, and the second cylindrical mirror in sequence, and then incident on the incident surface of the virtual imaging phase array. After the virtual imaging phase array is dispersed, it is converged into a linear beam by the third cylindrical mirror and incident on the adjustable slit. After spatial filtering to remove stray light by the adjustable slit, it is converged onto the area array camera by the converging lens.

[0013] Furthermore, the linear light spot focused by the second cylindrical mirror onto the incident surface of the virtual imaging phase array and the linear light spot formed after focusing by the objective lens are both parallel to the X-direction.

[0014] Furthermore, the filtering components are used to filter out reflected light and elastic background light, including but not limited to ultra-narrow bandwidth filters and atomic absorption cells.

[0015] Furthermore, the bright-field detection module includes a bright-field linear array light source assembly, a first filter, a first polarizing beam splitter, a first quarter-wave plate, a dichroic mirror, an objective lens, a second filter, a first cylindrical mirror, and a linear array camera, which together constitute the optical system.

[0016] The vertically polarized beam output by the bright-field linear array light source assembly can be converged into a linear beam after passing through the first filter, the first polarizing beam splitter, the first quarter-wave plate, the dichroic mirror and the objective lens in sequence, and then irradiate the sample surface. The beam formed by the reflection from the sample surface can be converged onto the linear array camera after passing through the objective lens, the dichroic mirror, the first quarter-wave plate, the first polarizing beam splitter, the second filter and the first cylindrical mirror in sequence.

[0017] Preferably, the object-side detection regions of both the Brillouin scattering detection module and the bright-field detection module are linear, and the focusing direction of the object-side line is along the X direction and maintains a consistent length.

[0018] Preferably, the displacement module includes a clamp for holding the sample and a drive device that enables the sample to move along the three directions of X, Y, and Z axes.

[0019] Preferably, the imaging and analysis module can store the received single wire harness measurement data, stitch together multiple wire harness measurement data to obtain the morphology map and mechanical stress distribution map of the sample, and perform real-time analysis, statistics and identification of the number and location of various defects; after identifying that the complete sample morphology has been measured, it feeds back information to the signal processing and feedback module, which can control the movement and stopping of the displacement module according to the feedback result.

[0020] Secondly, the present invention provides a defect detection method utilizing the wafer and chip defect detection system based on linear array Brillouin microscopy as described in the first aspect, as follows:

[0021] S1: After the system is started, the bright field linear array light source assembly provides collimated vertically polarized linear light source illumination. After being filtered by the first filter, the light beam is reflected by the first polarizing beam splitter. The reflected light beam becomes circularly polarized light after passing through the first quarter-wave plate, and then passes through the dichroic mirror. The light beam passing through the dichroic mirror is focused onto the sample surface by the objective lens. The light reflected from the sample surface is collected again by the objective lens, passes through the dichroic mirror, and reaches the first quarter-wave plate. The first quarter-wave plate converts the circularly polarized light reflected back from the sample into parallel polarized light, which can pass through the first polarizing beam splitter. The light beam passing through the first polarizing beam splitter is filtered by the second filter, and then focused into the linear array camera by the first cylindrical mirror.

[0022] Simultaneously, the Brillouin scattering linear array light source assembly provides collimated parallel polarized line illumination. After being filtered by the third filter, the beam is transmitted through the second polarizing beam splitter. The transmitted beam is converted from polarized light to circularly polarized light by the second quarter-wave plate, and then reflected by the dichroic mirror to the objective lens, where it is converged onto the sample surface. The light reflected from the sample surface is collected again by the objective lens, reflected by the dichroic mirror, and reaches the second quarter-wave plate. The second quarter-wave plate converts the circularly polarized light reflected back from the sample into vertically polarized light, enabling it to be reflected by the second polarizing beam splitter. The light beam is first emitted, then reflected by a mirror and enters the filter assembly. After being filtered by the filter assembly, the beam is focused by a second cylindrical mirror onto the incident surface of the virtual imaging phase array. After passing through the virtual imaging phase array, the linear light spot in the X direction disperses and expands in the Y direction, forming a two-dimensional spectral image. The two-dimensional spectral image is then re-converged into a linear light spot in the X direction by a third cylindrical mirror and focused onto an adjustable slit. The adjustable slit performs spatial filtering on the light spot, filtering out stray signals after dispersion in the Y direction. The light beam after passing through the adjustable slit is then converged into the area array camera by a converging lens.

[0023] During this process, the signal processing and feedback module receives the detection signals from the Brillouin scattering detection module and the bright field detection module in real time and processes them into single-beam measurement data. The imaging and analysis module performs imaging processing on the single-beam measurement data and feeds it back to the signal processing and feedback module. The signal processing and feedback module controls the displacement module according to the received feedback command, so that the displacement module moves the sample to directly below the objective lens and moves it to the optimal focusing position in the Z-axis direction. After focusing is completed, the signal processing and feedback module sends a command to stop the displacement module from moving.

[0024] S2: After the displacement module stops moving, the Brillouin scattering detection module and the bright-field detection module focus the beamline parallel to the X-direction onto the sample through the objective lens at the position (x) kj,y k The system reshapes and receives the returned linear beam; where j = 1, 2, ..., l, representing that a single linear array has l micro-points; k = 1, 2, ..., m, representing that there are a total of m measurement sites on the sample, requiring m measurements; the bright-field detection module directly acquires the light intensity information I of the returned linear beam through the linear array camera. LF (x kj ,y k The signal processing and feedback module then transmits the received two-dimensional spectral information to the signal processing and feedback module. The Brillouin scattering detection module acquires the dispersed two-dimensional spectral information via a planar array camera and transmits it to the signal processing and feedback module. The signal processing and feedback module further processes the received two-dimensional spectral information and extracts the Brillouin frequency shift ν for each micro-point. B (x kj ,y k ), Brillouin line width Γ B (x kj ,y k ) and Brillouin peak intensity G B (x kj ,y k The signal processing and feedback module sends the processed single-array information to the imaging and analysis module.

[0025] S3: The imaging and analysis module stores and stitches together the single-line harness measurement data for imaging processing. By comparing the four defect images obtained from the imaging (including one geometric defect image and three mechanical stress defect images, the three mechanical stress defect images are obtained by processing Brillouin frequency shift, Brillouin linewidth and Brillouin peak light intensity information respectively), the module identifies defects and determines whether the sample has been scanned.

[0026] If the sample is not fully scanned, the result is fed back to the signal processing and feedback module. The signal processing and feedback module sends a command to the displacement module to move along the scanning path and performs focusing processing according to step S1. When the displacement module stops moving, steps S2 and S3 are executed in sequence. If the sample is fully scanned, the result is fed back to the signal processing and feedback module. The signal processing and feedback module sends a command to the displacement module to stop moving, thus completing the defect detection of the sample.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1) This invention employs confocal line-scanning Brillouin microscopy, which can simultaneously measure hundreds of micro-points, resulting in a faster imaging speed than traditional single-point scanning Brillouin microscopy. Compared with existing line-scanning Brillouin microscopy, the confocal line-scanning structure can image opaque samples, making it possible to apply it to defect detection of wafers and chips.

[0029] 2) This invention can simultaneously perform bright-field line scanning and Brillouin line scanning imaging of wafer defects. Compared with traditional line scanning wafer defect detection systems, it adds Brillouin line scanning imaging, which can simultaneously acquire geometric defects and mechanical stress defects of wafers and chips, thereby improving the defect detection rate. Attached Figure Description

[0030] Figure 1 This is a simplified schematic diagram of the defect detection system of the present invention;

[0031] Figure 2 This is a schematic diagram of a detection module (including a Brillouin scattering detection module and a bright field detection module) in a defect detection system according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of a line scan imaging method for a Brillouin scattering detection module according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of a demodulation method for Brillouin scattering line scanning microscopy detection according to an embodiment of the present invention. In the diagram, 401 is the stress distribution map of the sample, 402 is the line beam map reflected back by the objective lens in the Brillouin scattering detection module, 403 is the two-dimensional spectral distribution map after dispersion by the virtual imaging phase array in the Brillouin scattering detection module, 404 is the Brillouin spectrum of a single micro-point after processing by the signal processing and feedback module, 405 is the Brillouin signal map of a single line beam after processing by the signal processing and feedback module, and 406 is the Brillouin elastic imaging map obtained after imaging by the imaging and statistical module.

[0034] The attached figures are labeled as follows: 101-Brillouin scattering detection module, 102-bright-field detection module, 103-sample, 104-displacement module, 105-signal processing and feedback module, 106-imaging and analysis module; 201-bright-field linear array light source assembly, 202-first filter, 203-first polarizing beam splitter, 204-first quarter-wave plate, 205-dichroic mirror, 206-objective lens, 207-second filter. 208-First cylindrical mirror, 209-Linear array camera, 210-Brillouin scattering linear array light source assembly, 211-Third filter, 212-Second polarizing beam splitter, 213-Second quarter-wave plate, 214-Reflector, 215-Filter assembly, 216-Second cylindrical mirror, 217-Virtual imaging phase array, 218-Third cylindrical mirror, 219-Adjustable slit, 220-Converging lens, 221-Area array camera. Detailed Implementation

[0035] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0036] First, the terms involved in this invention are explained: 1) Brillouin scattering refers to the scattering produced by the interaction of light waves and acoustic phonons in a sample. It is an inelastic scattering. After Brillouin scattering, a Brillouin frequency shift occurs and a Brillouin peak is generated. By measuring the frequency shift, linewidth, peak intensity, and other information of the Brillouin peak energy, information about the acoustic, thermodynamic, and viscoelastic properties of the sample can be obtained. 2) Linear confocal, compared with point confocal, uses a line beam to illuminate the sample in one dimension to simultaneously measure multiple points, which can improve the imaging speed. By filtering out stray light from non-focusing layers in the sample imaging beam through a confocal slit, the imaging contrast and resolution are improved. 3) Polarizing beam splitter prism is an optical element used to separate the horizontal and vertical polarization components of a beam. Specifically, it transmits parallel polarized light and reflects vertical polarized light. In this invention, vertical polarized light (S-beam) and parallel polarized light (P-beam) are defined with reference to the incident plane of the polarizing beam splitter prism.

[0037] like Figure 1 As shown, this invention provides a wafer and chip defect detection system based on linear array Brillouin microscopy. The defect detection system mainly includes a Brillouin scattering detection module 101, a bright field detection module 102, a displacement module 104, a signal processing and feedback module 105, and an imaging and analysis module 106. The Brillouin scattering detection module 101 and the bright-field detection module 102 are used to detect the sample 103 and transmit the collected detection signals to the signal processing and feedback module 105. The signal processing and feedback module 105 is used to process the obtained detection signals, extract the data for imaging and send it to the imaging and analysis module 106, and issue commands to control the movement of the displacement module 104. The displacement module 104 can drive the sample 103 to move along a specific trajectory according to the signal received from the signal processing and feedback module 105. The imaging and analysis module 106 is used to store and display the obtained linear array information, and to perform synchronous analysis on the imaging results, identify various defects and record information such as type, quantity and location. When the complete sample morphology has been measured, the module feeds back information to the signal processing and feedback module 105. The signal processing and feedback module 105 controls the movement and stopping of the displacement module 104 according to the feedback results from the imaging and analysis module 106.

[0038] Specifically, sample 103 is placed on displacement module 104, and signal processing and feedback module 105 can control the movement of sample 103 through displacement module 104. Brillouin scattering detection module 101 is used to detect the Brillouin spectrum information on the surface of sample 103, thereby obtaining its mechanical stress defect distribution information. Bright field detection module 102 is used to detect the bright field light intensity information on the surface of sample 103, thereby obtaining its geometric defect distribution information. Both Brillouin scattering detection module and bright field detection module are connected to signal processing and feedback module 105, and can transmit the collected detection signals to signal processing and feedback module 105 for preliminary processing to obtain single-beam measurement data. Signal processing and feedback module 105 is connected to imaging and analysis module 106, and transmits single-beam measurement data to imaging and analysis module 106. Imaging and analysis module 106 can receive, store, and image process single-beam measurement data, and can also feed the results back to signal processing and feedback module 105.

[0039] like Figure 2 and 3 As shown, the Brillouin scattering detection module 101 mainly includes a Brillouin scattering linear array light source assembly 210, a third filter 211, a second polarizing beam splitter 212, a second quarter-wave plate 213, a dichroic mirror 205, an objective lens 206, a reflecting mirror 214, a filter assembly 215, a second cylindrical mirror 216, a virtual imaging phase array 217, a third cylindrical mirror 218, an adjustable slit 219, a converging lens 220, and an area array camera 221, which together constitute the optical system.

[0040] Specifically, the parallel polarized beam output from the Brillouin scattering linear array light source component 210 can sequentially pass through the third filter 211, the second polarizing beam splitter 212, the second quarter-wave plate 213, the dichroic mirror 205, and the objective lens 206, and then converge into a linear beam that illuminates the surface of the sample 103 (wafer or chip). The beam formed by reflection from the surface of the sample 103 can sequentially pass through the objective lens 206, the dichroic mirror 205, the second quarter-wave plate 213, the second polarizing beam splitter 212, the mirror 214, the filter component 215, and the second cylindrical mirror 216, and then converge into a linear beam that is incident on the incident surface of the virtual imaging phase array 217. After being dispersed by the virtual imaging phase array 217, it is then converged into a linear beam by the third cylindrical mirror 218 and incident on the adjustable slit 219. After being spatially filtered by the adjustable slit 219 to remove stray light, it is then converged onto the area array camera 221 by the converging lens 220.

[0041] In the actual testing process, the bright-field linear array light source assembly 201 provides collimated vertically polarized linear illumination. After being filtered by the first filter 202, the light beam is reflected by the first polarizing beam splitter 203. The reflected beam passes through the first quarter-wave plate 204 and becomes circularly polarized light, then passes through the dichroic mirror 205. The dichroic mirror 205 is designed to transmit the wavelength of the bright-field illumination and reflect the wavelength of the Brillouin scattering illumination. The light beam passing through the dichroic mirror 205 is converged onto the surface of the sample 103 by the objective lens 206. The light reflected from the surface of the sample 103 is collected again by the objective lens 206, passes through the dichroic mirror 205, and reaches the first quarter-wave plate 204. The first quarter-wave plate 204 converts the circularly polarized light reflected back from the sample 103 into P-beams, allowing them to pass through the first polarizing beam splitter 203. The use of the first polarizing beam splitter 203 enables complete reflection and transmission of light, improving light utilization. The light beam passing through the first polarizing beam splitter 203 is filtered by the second filter 207, and then converged into the line scan camera 209 by the first cylindrical mirror 208. The first cylindrical mirror 208 converges the light beam into a linear spot, which is parallel to the linear spot focused by the objective lens 206. This completes the measurement of a single line region by a bright-field detection module.

[0042] In a preferred embodiment, the filtering component can filter out reflected light and elastic background light, including but not limited to ultra-narrow bandwidth filters, atomic absorption cells, etc. Alternatively, it can eliminate elastic background light by adding an adjustable optical path difference reference light to perform Michelson destructive interference with the measured light, thereby improving the contrast of the Brillouin peak. The second cylindrical mirror focuses the reflected beam into a linear beam in the X direction and incident it into a virtual imaging phase array (parallel to the X direction and tilted at a certain angle to the Y direction). The virtual imaging phase array disperses the linear beam, causing it to produce large-angle dispersion in the Y direction, obtaining a two-dimensional spectral image. By measuring the two-dimensional spectral image using an area array camera, the Brillouin spectrum of each micro-point in the X direction of the linear beam can be obtained. The linear spot focused by the second cylindrical mirror 216 onto the incident surface of the virtual imaging phase array 217 and the linear spot formed after focusing by the objective lens 206 are both parallel to the X direction.

[0043] like Figure 2 As shown, the bright field detection module 102 mainly includes a bright field linear array light source assembly 201, a first filter 202, a first polarizing beam splitter 203, a first quarter-wave plate 204, a dichroic mirror 205, an objective lens 206, a second filter 207, a first cylindrical mirror 208, and a linear array camera 209, which together constitute the optical system.

[0044] Specifically, the vertically polarized beam output by the brightfield linear array light source assembly 201 can be converged into a linear beam after passing through the first filter 202, the first polarizing beam splitter 203, the first quarter-wave plate 204, the dichroic mirror 205 and the objective lens 206 in sequence, and then irradiate the surface of the sample 103. The beam formed by the reflection of the sample 103 surface can be converged onto the linear array camera 209 after passing through the objective lens 206, the dichroic mirror 205, the first quarter-wave plate 204, the first polarizing beam splitter 203, the second filter 207 and the first cylindrical mirror 208 in sequence.

[0045] like Figure 3 As shown, in the actual detection process, the Brillouin scattering linear array light source assembly 210 provides a collimated parallel polarized line light source. Figure 3 Illuminated by P-rays, the light beam is filtered by the third filter 211 and then transmitted through the second polarizing beam splitter 212. The transmitted beam is converted from polarized light to circularly polarized light by the second quarter-wave plate 213, and then reflected by the dichroic mirror 205 to the objective lens 206. The objective lens 206 converges the light onto the surface of the sample 103. The light reflected from the surface of the sample 103 is collected again by the objective lens 206, reflected by the dichroic mirror 205, and reaches the second quarter-wave plate 213. The second quarter-wave plate 213 converts the circularly polarized light reflected from the sample 103 into vertically polarized light. Figure 3 The beam is filtered by the second polarizing beam splitter 212, then reflected by the mirror 214, and finally incident on the filter assembly 215. The filter assembly 215 has an ultra-narrow linewidth filtering function, which can suppress elastic scattering light caused by reflection from the confocal structure, thereby improving the extinction ratio of the Brillouin signal. After being filtered by the filter assembly 215, the beam is linearly focused by the second cylindrical mirror 216 onto the incident surface of the virtual imaging phase array 217. The linearly focused beam here is parallel to the linearly focused beam of the objective lens 206 (both along the X direction, such as...). Figure 3 (As shown). After passing through the virtual imaging phase array 217, the linear light spot in the X direction disperses and expands in the Y direction, forming a two-dimensional spectral image, as shown. Figure 3 As shown, the two-dimensional spectral image is then refocused into a linear spot in the X direction by the third cylindrical mirror 218 and focused onto the adjustable slit 219. The adjustable slit 219 performs spatial filtering on the spot, removing stray signals after dispersion in the Y direction. The light rays after passing through the adjustable slit 219 are then focused into the area array camera 221 by the converging lens 220. This completes the measurement of a single linear region by a Brillouin scattering detection module.

[0046] In a preferred embodiment, the Brillouin scattering linear array light source assembly and the bright-field linear array light source assembly can obtain linear light spots with consistent orientation (both along the X direction) at the sample under test through shaping and processing by the optical systems in their respective modules, and the light source needs to be sufficiently uniform. That is, the object-side detection regions of the Brillouin scattering detection module 101 and the bright-field detection module 102 are both linear, and the focusing direction of the object-side lines is both along the X direction and maintains a consistent length. The light source wavelengths of the bright-field detection module and the Brillouin scattering detection module are different, and their respective light source wavelengths are introduced into their respective detectors for reception by a dichroic mirror. The linear array camera can measure the reflected bright-field beam and obtain the bright-field light intensity at each micro-point in the X direction of the linear light.

[0047] In a preferred embodiment, the signal processing and feedback module can process the results measured by the array camera and the line scan camera. By processing the results returned by the array camera, Brillouin information of each micro-point in the X-direction can be obtained, including Brillouin frequency shift, Brillouin peak linewidth, and Brillouin peak intensity. By processing the results returned by the line scan camera, bright-field light intensity information of each micro-point in the X-direction can be obtained. The signal processing and feedback module transmits the processed single-shot beam measurement data to the imaging and analysis module and sends commands to the displacement module to control its movement.

[0048] In a preferred embodiment, the displacement module 104 mainly includes a clamp for holding the sample 103 and a drive device that enables the sample 103 to move along the three directions of X, Y, and Z axes. In turn, it can control the position of the sample according to the control instructions of the signal processing and feedback module, thereby realizing line scanning imaging of the sample.

[0049] In a preferred embodiment, the imaging and analysis module 106 can store the received single-shot wire harness measurement data, stitch together multiple wire harness measurement data to obtain a geometric morphology map and mechanical stress distribution map of the sample 103, and perform real-time analysis, statistics, and identification of the quantity and location of various defects (scratches, particles, grooves, stress unevenness, etc.). After identifying that the complete morphology of the sample 103 has been measured, feedback information is sent to the signal processing and feedback module 105, which can control the movement and stopping of the displacement module 104 according to the feedback result.

[0050] The method for detecting sample defects using the aforementioned defect detection system is as follows:

[0051] S1: Focus. The specific steps are as follows:

[0052] After the system starts, the Brillouin scattering detection module, bright-field detection module, and signal processing and feedback module all begin operation. The signal processing and feedback module 105 receives the detection signals from the Brillouin scattering detection module 101 and the bright-field detection module 102 in real time and processes them into single-shot beam measurement data. The imaging and analysis module 106 performs imaging processing on the single-shot beam measurement data and feeds it back to the signal processing and feedback module 105. Based on the received feedback command, the signal processing and feedback module 105 controls the displacement module 104, causing it to move the sample 103 directly below the objective lens 206 and to the optimal focusing position along the Z-axis. This optimal focusing position is one that allows both the line scan camera and the area scan camera to capture clear images. After focusing is complete, the signal processing and feedback module 105 sends a command to stop the displacement module 104.

[0053] S2: Single linear array information acquisition. This step is detailed as follows:

[0054] After the displacement module 104 stops moving, the Brillouin scattering detection module 101 and the bright field detection module 102 focus the beamline parallel to the X direction onto the sample 103 at a position (x) through the same confocal objective lens 206. kj ,y k The system reshapes and receives the returned linear beam. Here, j = 1, 2, ..., l represents that a single linear array has l micropoints; k = 1, 2, ..., m represents that there are a total of m measurement sites on the sample, requiring m measurements. The bright-field detection module 102 directly acquires the light intensity information of the returned linear beam through the linear array camera 209. LF (x kj ,y k The signal processing and feedback module 101 transmits the data to the signal processing and feedback module 105. The Brillouin scattering detection module 101 acquires the two-dimensional spectral information after dispersion by the virtual imaging phase array 217 via the area array camera 221 and transmits it to the signal processing and feedback module 105. The signal processing and feedback module 105 further processes the received two-dimensional spectral information and extracts the Brillouin frequency shift ν of each micro-point. B (x kj ,y k ), Brillouin line width Γ B (x kj ,y k ) and Brillouin peak intensity G B (x kj ,y k The signal processing and feedback module 105 sends the processed single linear array information to the imaging and analysis module 106.

[0055] S3: Line scanning, imaging, and statistical analysis. This step is detailed below:

[0056] The imaging and analysis module 106 stores and stitches together the single-shot wire harness measurement data for imaging processing. Simultaneously, it statistically analyzes, records, and displays the number, type, and location of defects in the currently completed imaging results, and determines whether the sample scan is complete. If the sample 103 is not fully scanned, the result is fed back to the signal processing and feedback module 105. The signal processing and feedback module 105 sends a command to the displacement module 104, instructing it to move along the scanning path and perform focusing processing according to step S1. After the displacement module 104 stops moving, steps S2 and S3 are executed sequentially. If the sample 103 is fully scanned, the result is fed back to the signal processing and feedback module 105. The signal processing and feedback module 105 sends a command to the displacement module 104, instructing it to stop moving, thus completing the defect detection of the sample 103.

[0057] like Figure 4 The image illustrates the demodulation imaging process of Brillouin scattering line scanning microscopy in one embodiment of the present invention, as detailed below:

[0058] Wafers or chips have specific stress distributions, such as Figure 4 As shown in 401, the Brillouin scattered beam is focused into an X-direction linear spot onto the sample 103 by objective lens 206. The incident light interacts with the acoustic phonons in the sample to produce Brillouin scattering. The backscattered Brillouin light is captured by objective lens 206 and returns along the same path, resulting in a linear beam carrying Brillouin scattering information, as shown in 401. Figure 4 As shown in Figure 402, the longitudinal modulus M(ν) of a single micro-point in the sample is related to the Brillouin scattering information and can be expressed as:

[0059] M(ν)=M'(ν)+iM””ν)

[0060] In the formula, ν is the frequency, M' is the storage modulus, M” is the loss modulus, and i is the imaginary unit. The storage modulus characterizes the rigidity and elastic properties of the material and is related to the Brillouin frequency shift ν. B For confocal optical paths, the Brillouin scattering angle is 180°, therefore the storage modulus M' at a single point in the sample is related to the Brillouin frequency shift ν. B The relationship is:

[0061]

[0062] In the formula, λ0 is the incident light wavelength of the Brillouin scattering detection module, n is the refractive index of the sample, and ρ is the mass density of the sample. Therefore, the storage modulus at a single point can be calculated by measuring the Brillouin frequency shift.

[0063] Loss modulus characterizes the longitudinal viscosity properties of a material and is related to both Brillouin frequency shift and linewidth. For confocal optical paths, the loss modulus M" at a single point in the sample is related to the Brillouin frequency shift ν.B and line width Γ B The relationship is:

[0064]

[0065] Therefore, the loss modulus at that point can be calculated by measuring the Brillouin frequency shift and the Brillouin linewidth.

[0066] In addition, the light intensity G of the Brillouin spectral peak B It can also characterize relevant information about the sample. Therefore, by extracting the Brillouin frequency shift, Brillouin linewidth, and Brillouin peak gain from the Brillouin spectrum, information on different mechanical properties of the sample can be obtained. Finally, the mechanical stress map of the sample is plotted through the imaging and analysis module, including the Brillouin frequency shift map (i.e., storage modulus map), the Brillouin linewidth map (i.e., loss modulus map), and the Brillouin peak intensity map.

[0067] However, since the Brillouin shift is only on the order of GHz, it cannot be resolved by a camera. Therefore, a virtual imaging phase array is needed for dispersion separation. Linear light along the X-direction is incident on a virtual imaging phase array (parallel to the X-direction and tilted at a certain angle to the Y-direction). The virtual imaging phase array disperses the linear light, causing it to produce large-angle dispersion in the Y-direction, thus obtaining a two-dimensional spectral image, such as... Figure 4 As shown in 403, the two-dimensional spectral image is measured by an area array camera, and the measured data is then transmitted to the signal processing and feedback module 105 for processing. This allows the acquisition of the Brillouin spectrum at each micro-point in the X-direction of the linear light, as shown in... Figure 4 As shown in 404, the signal processing and feedback module 105 extracts the Brillouin frequency shift value ν of each micro-point. B Brillouin linewidth Γ B Brillouin peak light intensity G B The data is then transmitted to the imaging and analysis module 106 to plot the relationship curves between a single X-ray beam and these three parameters, as shown below. Figure 4 As shown in 405, the imaging and analysis module 106 stitches together multiple line harness measurement data to obtain a mechanical stress distribution map of the sample through line scanning, as shown in Figure 405. Figure 4 As shown in 406 ( Figure 4 The Chinese version 406 only shows one simple diagram, but in reality, it can show three diagrams, including the Brillouin frequency shift diagram, the Brillouin linewidth diagram, and the Brillouin intensity diagram. It can also perform real-time analysis of the imaging results and count the number and location of defects related to the elastic modulus.

[0068] Therefore, this invention can perform line-scan confocal measurements of the mechanical properties of samples such as wafers and opaque chips through the Brillouin scattering detection module, which greatly improves the speed of Brillouin scattering detection; the combination of bright-field linear array detection and Brillouin scattering linear array detection can simultaneously obtain the geometric defects and mechanical stress defects of wafer and chip samples, thus broadening the parameters for defect detection.

[0069] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A wafer and chip defect detection system based on linear Brillouin microscopy, characterized in that, It includes a Brillouin scattering detection module (101), a bright field detection module (102), a displacement module (104), a signal processing and feedback module (105), and an imaging and analysis module (106). The sample (103) is placed on the displacement module (104), and the signal processing and feedback module (105) can control the movement of the sample (103) through the displacement module (104); the Brillouin scattering detection module (101) obtains the mechanical stress defect distribution information by detecting the Brillouin spectrum information on the surface of the sample (103), and the bright field detection module (102) obtains the geometric defect distribution information by detecting the bright field light intensity information on the surface of the sample (103); the signal processing and feedback module (105) is connected to the Brillouin scattering detection module (101) and the bright field detection module (102) respectively, and is used to receive the collected detection signals and process them into single-beam measurement data; the imaging and analysis module (106) is connected to the signal processing and feedback module (105), and is used to receive, store and image process the single-beam measurement data, and can also feed the results back to the signal processing and feedback module (105). The Brillouin scattering detection module (101) includes a Brillouin scattering linear array light source assembly (210) that together constitute the optical system, a third filter (211), a second polarizing beam splitter (212), a second quarter-wave plate (213), a dichroic mirror (205), an objective lens (206), a mirror (214), a filter assembly (215), a second cylindrical mirror (216), a virtual imaging phase array (217), a third cylindrical mirror (218), an adjustable slit (219), a converging lens (220), and an area array camera (221). The parallel polarized beam output from the Brillouin scattering linear array light source assembly (210) can be converged into a linear beam after passing through the third filter (211), the second polarizing beam splitter (212), the second quarter-wave plate (213), the dichroic mirror (205), and the objective lens (206) in sequence, and then irradiate the surface of the sample (103). The beam formed by reflection from the surface of the sample (103) can then pass through the objective lens (206), the dichroic mirror (205), the second quarter-wave plate (213), and the second polarizing beam splitter (206) in sequence. After being focused into a linear beam by a beam splitter (212), a reflector (214), a filter assembly (215), and a second cylindrical mirror (216), the light is incident on the incident surface of a virtual imaging phase array (217). After being dispersed by the virtual imaging phase array (217), the light is focused into a linear beam by a third cylindrical mirror (218) and incident on an adjustable slit (219). After being spatially filtered by the adjustable slit (219) to remove stray light, the light is then focused onto an area array camera (221) by a converging lens (220).

2. The wafer and chip defect detection system based on linear Brillouin microscopy according to claim 1, characterized in that, The linear spot formed by the second cylindrical mirror (216) focusing onto the incident surface of the virtual imaging phase array (217) and the linear spot formed by the objective lens (206) focusing are both parallel to the X direction.

3. The wafer and chip defect detection system based on linear array Brillouin microscopy according to claim 1, characterized in that, The filter assembly (215) is used to filter out reflected light and elastic background light, including but not limited to an ultra-narrow bandwidth filter and an atomic absorption cell.

4. The wafer and chip defect detection system based on linear Brillouin microscopy according to claim 1, characterized in that, The bright field detection module (102) includes a bright field linear array light source assembly (201) that together constitutes the optical system, a first filter (202), a first polarizing beam splitter (203), a first quarter-wave plate (204), a dichroic mirror (205), an objective lens (206), a second filter (207), a first cylindrical mirror (208), and a linear array camera (209). The vertically polarized beam output by the bright field linear array light source assembly (201) can be converged into a linear beam after passing through the first filter (202), the first polarizing beam splitter (203), the first quarter-wave plate (204), the dichroic mirror (205) and the objective lens (206) in sequence and irradiating the surface of the sample (103). The beam formed by the reflection of the sample (103) surface can be converged onto the linear array camera (209) after passing through the objective lens (206), the dichroic mirror (205), the first quarter-wave plate (204), the first polarizing beam splitter (203), the second filter (207) and the first cylindrical mirror (208) in sequence.

5. The wafer and chip defect detection system based on linear Brillouin microscopy according to claim 1, characterized in that, The object-side detection regions of both the Brillouin scattering detection module (101) and the bright-field detection module (102) are linear, and the focusing direction of the object-side lines is along the X direction and maintains a consistent length.

6. The wafer and chip defect detection system based on linear Brillouin microscopy according to claim 1, characterized in that, The displacement module (104) includes a clamp for holding the sample (103) and a drive device that enables the sample (103) to move along the three directions of X, Y, and Z axes.

7. The wafer and chip defect detection system based on linear array Brillouin microscopy according to claim 1, characterized in that, The imaging and analysis module (106) can store the received single wire harness measurement data, stitch together multiple wire harness measurement data to obtain the morphology map and mechanical stress distribution map of the sample (103), and perform real-time analysis, statistics and identification of the number and location of various defects; after identifying the morphology of the complete sample (103) that has been measured, it feeds back information to the signal processing and feedback module (105), and the signal processing and feedback module (105) can control the movement and stop of the displacement module (104) according to the feedback result.

8. A defect detection method using the wafer and chip defect detection system based on linear array Brillouin microscopy as described in any one of claims 1-7, characterized in that, Specifically as follows: S1: After the system is started, the bright-field linear array light source assembly (201) provides collimated vertically polarized linear light source illumination. After being filtered by the first filter (202), the light beam is reflected by the first polarizing beam splitter (203). The reflected light beam becomes circularly polarized after passing through the first quarter-wave plate (204), and then passes through the dichroic mirror (205). The light beam passing through the dichroic mirror (205) is converged on the surface of the sample (103) by the objective lens (206); the surface of the sample (103) reflects... The light is collected again by the objective lens (206), passes through the dichroic mirror (205) and reaches the first quarter-wave plate (204). The first quarter-wave plate (204) converts the circularly polarized light reflected back from the sample (103) into parallel polarized light, which can pass through the first polarizing beam splitter (203). The light beam passing through the first polarizing beam splitter (203) is filtered by the second filter (207) and then converged into the line array camera (209) by the first cylindrical mirror (208). Meanwhile, the Brillouin scattering linear array light source assembly (210) provides collimated parallel polarized line light source illumination. After being filtered by the third filter (211), the light beam is transmitted by the second polarizing beam splitter (212). The transmitted light beam is converted from polarized light to circularly polarized light by the second quarter-wave plate (213), and then reflected by the dichroic mirror (205) to the objective lens (206). The objective lens (206) converges the light onto the surface of the sample (103). The light reflected from the surface of the sample (103) is collected again by the objective lens (206), reflected by the dichroic mirror (205), and reaches the second quarter-wave plate (213). The second quarter-wave plate (213) converts the circularly polarized light reflected from the sample (103) into vertically polarized light, which can be reflected by the second polarizing beam splitter (212), and then reflected by the mirror (214) before entering the filter assembly (215). After being filtered by the filter assembly (215), the beam is linearly focused into space by the second cylindrical mirror (216). The incident surface of the imaging phase array (217); after passing through the virtual imaging phase array (217), the linear light spot in the X direction is dispersed and expanded in the Y direction to form a two-dimensional spectral image; the two-dimensional spectral image is then re-converged into a linear light spot in the X direction by the third cylindrical mirror (218) and focused onto the adjustable slit (219); the adjustable slit (219) performs spatial filtering on the light spot to filter out stray signals after dispersion in the Y direction; the light rays after passing through the adjustable slit (219) are converged into the area array camera (221) by the converging lens (220); During this process, the signal processing and feedback module (105) receives the detection signals sent back by the Brillouin scattering detection module (101) and the bright field detection module (102) in real time and processes them into single-beam measurement data. The imaging and analysis module (106) performs imaging processing on the single-beam measurement data and feeds it back to the signal processing and feedback module (105). The signal processing and feedback module (105) controls the displacement module (104) according to the received feedback command, so that the displacement module (104) moves the sample (103) directly below the objective lens (206) and moves it to the optimal focusing position in the Z-axis direction. After focusing is completed, the signal processing and feedback module (105) sends a command to stop the displacement module (104) from moving. S2: After the displacement module (104) stops moving, the Brillouin scattering detection module (101) and the bright field detection module (102) focus the beamline parallel to the X direction onto the sample (103) through the objective lens (206). x kj , y k ), and reshape and receive the returned linear beam; among which, j =1,2,..., l This represents a single linear array having l A tiny dot; k =1,2,..., m This means that there are a total of [number] samples on the sample. m Each measurement site needs to be measured. m The second measurement; the bright field detection module (102) directly collects the light intensity information of the returned linear beam through the line array camera (209). I LF ( x kj , y k The signal processing and feedback module (105) then transmits the received two-dimensional spectral information to the signal processing and feedback module (105). The Brillouin scattering detection module (101) acquires the two-dimensional spectral information after dispersion by the virtual imaging phase array (217) through the area array camera (221) and transmits it to the signal processing and feedback module (105). The signal processing and feedback module (105) further processes the received two-dimensional spectral information and extracts the Brillouin frequency shift of each micro-point. ν B ( x kj , y k Brillouin line width Γ B ( x kj , y k ) and Brillouin peak intensity G B ( x kj , y k The signal processing and feedback module (105) sends the processed single linear array information to the imaging and analysis module (106). S3: The imaging and analysis module (106) stores and stitches together the single-line harness measurement data for imaging processing. It identifies defects by comparing the defect maps obtained from the imaging and determines whether the sample (103) has been scanned. The defect map includes a geometric defect map and a mechanical stress defect map obtained by processing Brillouin frequency shift, Brillouin linewidth, and Brillouin peak intensity information. If the sample (103) has not been scanned, the result is fed back to the signal processing and feedback module (105). The signal processing and feedback module (105) sends an instruction to the displacement module (104) to move along the scanning path and performs focusing processing according to step S1. When the displacement module (104) stops moving, steps S2 and S3 are executed in sequence. If the sample (103) has been scanned, the result is fed back to the signal processing and feedback module (105). The signal processing and feedback module (105) sends an instruction to the displacement module (104) to stop moving, thus completing the defect detection of the sample (103).

Images