Dark-field confocal microscopy measurement device and method based on differential fractional-order vortex beam

Abstract

The present invention discloses a dark field confocal microscopic measurement device and method based on differential fractional vortex beams, which relates to the field of optical precision measurement. The device comprises: a fractional vortex light module, which is used to generate a first fractional vortex light and a second fractional vortex light; an optical scanning module, which is used to scan the sample with the first fractional vortex light and the second fractional vortex light respectively, to obtain a first signal return light and a second signal return light; a dark field detection module, which is used to perform dark field detection on the first signal return light and the second signal return light respectively, to obtain a first fractional scattering dark field image and a second fractional scattering dark field image; a differential dark field scattering image determination module, which is used to perform differential dark field scattering image on the first fractional scattering dark field image and the second fractional scattering dark field image, to obtain a differential dark field scattering image; and a defect determination module, which is used to process the differential dark field scattering image to obtain sample defects. The present invention can improve the imaging signal-to-noise ratio and the sensitivity of defect detection.

Description

Technical Field

[0001] The present invention relates to the technical field of optical precision measurement, and in particular to a dark field confocal microscopic measurement device and method based on differential fractional-order vortex beams. Background Art

[0002] Interlayer defects (such as holes and stacking faults) in 3D integrated circuits can easily lead to a decrease in the electrical performance and life of 3D integrated circuits. The detection of interlayer defects can ensure the yield of semiconductor 3D integrated circuit products. Confocal microscopy measurement technology can be used for non-destructive defect detection of 3D integrated circuits due to its 3D tomography capability.

[0003] However, when using traditional confocal microscopy measurement technology to detect interlayer defects, the reflected light from the semiconductor surface easily overwhelms the scattered light from the interlayer defects, resulting in insufficient signal-to-noise ratio for interlayer defect detection and limited detection sensitivity.

[0004] Dark field confocal microscopy has the advantages of good optical tomography, high imaging resolution and high imaging contrast brought by dark background, and has become an important means of non-destructive three-dimensional detection of semiconductors. It can effectively separate surface reflected light and interlayer scattered light. However, ordinary optical dark field confocal microscopy has a low response rate to tiny defects and can only detect defects with a scale greater than 50nm. Smaller defects are easily submerged in background noise, and the defect detection rate is insufficient.

[0005] Therefore, how to more comprehensively characterize the interlayer defect characteristics of three-dimensional integrated circuits and achieve high-sensitivity defect detection is an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0006] The purpose of the present invention is to provide a dark-field confocal microscopy measurement device and method based on differential fractional-order vortex beams, which can improve the imaging signal-to-noise ratio and enhance the sensitivity of defect detection.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] In a first aspect, the present invention provides a dark-field confocal microscopy measurement device based on a differential fractional-order vortex beam, wherein the dark-field confocal microscopy measurement device based on a differential fractional-order vortex beam comprises: a fractional-order vortex light module, an optical scanning module, a dark-field detection module, a differential dark-field scattering image determination module, and a defect determination module.

[0009] The fractional-order vortex light module is used to generate a first fractional-order vortex light and a second fractional-order vortex light; the first fractional-order vortex light is light generated by superimposing a first vortex phase and a blazed grating phase; the second fractional-order vortex light is light generated by superimposing a second vortex phase and a blazed grating phase.

[0010] The optical scanning module is used to first transmit the first fractional-order vortex light to the sample for scanning to obtain a first signal return light, and then transmit the second fractional-order vortex light to the sample for scanning to obtain a second signal return light.

[0011] The dark field detection module is used to perform dark field detection on the first signal return light and the second signal return light respectively to obtain a first fractional-order scattering dark field image and a second fractional-order scattering dark field image.

[0012] The differential dark field scattering image determination module is used to differentiate the first fractional-order scattering dark field image and the second fractional-order scattering dark field image to obtain a differential dark field scattering image.

[0013] The defect determination module is used to process the differential dark field scattering image to obtain sample defects.

[0014] Optionally, the fractional-order vortex optical module includes: a laser, a half-wave plate, a polarizer, a reflector, a first non-polarizing beam splitter, a spatial light modulator and a beam expander.

[0015] The laser is used to output visible light band laser. After the visible light band laser passes through the half-wave plate, the polarizer, the reflector, the first non-polarizing beam splitter and the spatial light modulator in sequence, fractional-order vortex light is obtained. The fractional-order vortex light includes: first fractional-order vortex light and second fractional-order vortex light. After the fractional-order vortex light is expanded by the beam expander, expanded fractional-order vortex light is obtained. The expanded fractional-order vortex light is transmitted to the optical scanning module.

[0016] Optionally, the loading phase distribution of the spatial light modulator is: superposition of vortex phase and blazed grating phase.

[0017] Optionally, the optical scanning module includes: a second non-polarizing beam splitter, a scanning galvanometer, a scanning lens, a tube lens and an objective lens.

[0018] The expanded fractional-order vortex light sequentially passes through the second non-polarization beam splitter, the scanning galvanometer, the scanning lens, the tube lens, the objective lens and the sample to obtain signal return light.

[0019] The signal return light is collected by the objective lens, and after passing through the tube lens, the scanning lens, the scanning galvanometer and the second non-polarizing beam splitter, a transmitted signal return light is obtained; and the transmitted signal return light is transmitted to the dark field detection module.

[0020] Optionally, the dark field detection module includes: an aperture, a focusing lens, a pinhole and a photomultiplier tube.

[0021] The transmitted signal return light sequentially passes through the aperture, the focusing lens, the pinhole and the photomultiplier tube for dark field detection to obtain a fractional-order scattered dark field image.

[0022] Optionally, the dark-field confocal microscopy measurement device based on differential fractional-order vortex beam further includes: an axial translation stage.

[0023] The axial translation stage is used to move the sample.

[0024] In the second aspect, the present invention provides a dark-field confocal microscopy measurement method based on a differential fractional-order vortex beam, and the dark-field confocal microscopy measurement method based on a differential fractional-order vortex beam is implemented based on the above-mentioned dark-field confocal microscopy measurement device based on a differential fractional-order vortex beam, and the dark-field confocal microscopy measurement method based on a differential fractional-order vortex beam includes.

[0025] A fractional-order vortex light module is used to generate a first fractional-order vortex light; the first fractional-order vortex light is light generated by superposition of the first vortex phase and the blazed grating phase.

[0026] The first fractional-order vortex light is transmitted to the sample by using an optical scanning module for scanning to obtain a first signal return light.

[0027] A dark field detection module is used to perform dark field detection on the first signal return light to obtain a first fractional-order scattered dark field image.

[0028] A second fractional-order vortex light is generated by using a fractional-order vortex light module; the second fractional-order vortex light is light generated by superposition of the second vortex phase and the blazed grating phase.

[0029] The second fractional-order vortex light is transmitted to the sample by an optical scanning module for scanning to obtain a second signal return light.

[0030] A dark field detection module is used to perform dark field detection on the second signal return light to obtain a second fractional-order scattering dark field image.

[0031] The first fractional-order scattering dark-field image and the second fractional-order scattering dark-field image are differentiated to obtain a differential dark-field scattering image.

[0032] The differential dark field scattering image is processed to obtain sample defects.

[0033] Optionally, the generating of the first fractional-order vortex light by using the fractional-order vortex light module specifically includes.

[0034] According to the visible light band laser output by the laser, the first loading phase distribution of the spatial light modulator in the fractional-order vortex optical module is determined.

[0035] A first fractional-order vortex light is generated according to the first loading phase distribution.

[0036] The first loading phase distribution is: 1 +Φ.

[0037] Among them, ψ 1 =m 1 φ,m 1 =m 0 +Δm,Φ=2πGx,ψ 1 is the first vortex phase, Φ is the blazed grating phase, m 1 is the first fractional order, φ is the angular polar coordinate of the liquid crystal surface of the spatial light modulator, m 0 is an integer, Δm is a constant, 0<Δm<0.5, G is the blazed grating constant, and x is the Cartesian coordinate in the horizontal direction of the liquid crystal surface of the spatial light modulator.

[0038] Optionally, the generating the second fractional-order vortex light by utilizing the fractional-order vortex light module specifically includes.

[0039] According to the visible light band laser output by the laser, the second loading phase distribution of the spatial light modulator in the fractional-order vortex optical module is determined.

[0040] According to the second loading phase distribution, a first fractional-order vortex light is generated.

[0041] The second loading phase distribution is: 2 +Φ.

[0042] Among them, ψ 2 =m 2 φ,m 2 =m 0 -Δm,Φ=2πGx,ψ 2 is the second vortex phase, Φ is the blazed grating phase, m 2 is the second fractional order, φ is the angular polar coordinate of the liquid crystal surface of the spatial light modulator, m 0 is an integer, Δm is a constant, 0<Δm<0.5, G is the blazed grating constant, and x is the Cartesian coordinate in the horizontal direction of the liquid crystal surface of the spatial light modulator.

[0043] Optionally, a transmission direction of the first fractional-order vortex light or the second fractional-order vortex light is determined by a blazed grating constant.

[0044] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0045] The present invention provides a dark field confocal microscopic measurement device and method based on differential fractional-order vortex beams, wherein a fractional-order vortex light module is used to obtain two fractional-order vortex lights according to the superposition of two vortex phases and a blazed grating phase, and then two fractional-order scattered dark field images can be obtained through an optical scanning module and a dark field detection module, and the two fractional-order scattered dark field images are differentiated to obtain a differential dark field scattered image with common mode noise suppression and improved sensitivity. Among them, a fractional-order vortex light module is used to illuminate the sample with fractional-order vortex light, and the fractional-order vortex light can be equivalent to the superposition of multiple integer-order vortex components, and multiple orders simultaneously participate in the interaction between light and matter, and generate coherent enhancement and coherent destructive effects between signal lights of each order, which can effectively improve the signal contrast of micro-nanoparticles; compared with the prior art, the present invention can effectively separate the sample surface reflection signal and the interface defect scattering signal, and the differential result of the two fractional-order scattered dark field images can be used to improve the imaging signal-to-noise ratio and the sensitivity of defect detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 A schematic structural diagram of a dark-field confocal microscopy measurement device based on a differential fractional-order vortex beam provided in one embodiment of the present invention.

[0048] Figure 2 A schematic flow chart of a dark-field confocal microscopy measurement method based on a differential fractional-order vortex beam is provided in accordance with an embodiment of the present invention.

[0049] Description of Figure Numbers.

[0050] 1-laser, 2-half-wave plate, 3-polarizer, 4-mirror, 5-first non-polarizing beam splitter, 6-spatial light modulator, 7-beam expander, 8-second non-polarizing beam splitter, 9-scanning galvanometer, 10-scanning lens, 11-tube lens, 12-objective lens, 13-sample, 14-axial translation stage, 15-aperture, 16-focusing lens, 17-pinhole, 18-photomultiplier tube. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] In an exemplary embodiment, Figure 1 As shown, the present invention provides a dark-field confocal microscopy measurement device based on a differential fractional-order vortex beam, and the dark-field confocal microscopy measurement device based on a differential fractional-order vortex beam comprises: a fractional-order vortex light module, an optical scanning module, a dark-field detection module, a differential dark-field scattering image determination module and a defect determination module.

[0054] The fractional-order vortex light module is used to generate a first fractional-order vortex light and a second fractional-order vortex light; the first fractional-order vortex light is light generated by superimposing a first vortex phase and a blazed grating phase; the second fractional-order vortex light is light generated by superimposing a second vortex phase and a blazed grating phase.

[0055] The optical scanning module is used to first transmit the first fractional-order vortex light to the sample 13 for scanning to obtain a first signal return light, and then transmit the second fractional-order vortex light to the sample 13 for scanning to obtain a second signal return light.

[0056] The dark field detection module is used to perform dark field detection on the first signal return light and the second signal return light respectively to obtain a first fractional-order scattering dark field image and a second fractional-order scattering dark field image.

[0057] The differential dark field scattering image determination module is used to differentiate the first fractional-order scattering dark field image and the second fractional-order scattering dark field image to obtain a differential dark field scattering image.

[0058] The defect determination module is used to process the differential dark field scattering image to obtain sample defects.

[0059] In an exemplary embodiment, the fractional-order vortex optical module includes: a laser 1, a half-wave plate 2, a polarizer 3, a reflector 4, a first non-polarizing beam splitter 5, a spatial light modulator 6 and a beam expander 7;

[0060] The laser 1 is used to output visible light band laser. After the visible light band laser passes through the half-wave plate 2, the polarizer 3, the reflector 4, the first non-polarizing beam splitter 5 and the spatial light modulator 6 in sequence, fractional-order vortex light is obtained. The fractional-order vortex light includes: first fractional-order vortex light and second fractional-order vortex light. After the fractional-order vortex light is expanded by the beam expander 7, expanded fractional-order vortex light is obtained. The expanded fractional-order vortex light is transmitted to the optical scanning module.

[0061] That is to say, the fractional-order vortex optical module is composed of, in order according to the light propagation direction: laser 1, half-wave plate 2, polarizer 3, reflector 4, first non-polarizing beam splitter 5, spatial light modulator 6 and beam expander 7.

[0062] Among them, laser 1 is used to emit a laser beam, and the wavelength of the laser beam is in the visible light band; half-wave plate 2 refers to a birefringent crystal with a certain thickness. When the normally incident light is transmitted, the phase difference between the ordinary light and the extraordinary light is equal to π or an odd multiple thereof. Such a chip is a half-wave plate 2, also called a half-wave plate. Polarizer 3 refers to polarized glass, which has excellent optical properties such as light transmittance. Half-wave plate 2 and polarizer 3 are used to adjust the polarization state of the laser in the visible light band to match the spatial light modulator 6. Reflector 4 is used to reflect the light beam. The first non-polarizing beam splitter 5 only separates the energy of the incident light. The polarization state of the two emitted light beams does not have a specific change compared to the incident light, so the light is only split. The spatial light modulator 6 (Spatial Light Modulator, SLM) can modulate a certain parameter of the light field through liquid crystal molecules under active control, such as by modulating the amplitude of the light field, modulating the phase through the refractive index, modulating the polarization state through the rotation of the polarization plane, or realizing the conversion of incoherent-coherent light, so as to write certain information into the light wave and achieve the purpose of light wave modulation. It can conveniently load information into a one-dimensional or two-dimensional light field, and use the advantages of wide bandwidth and multi-channel parallel processing of light to quickly process the loaded information. It is a core component of real-time optical information processing, optical interconnection, optical computing and other systems. The loading phase distribution of the spatial light modulator 6 is: the superposition of the vortex phase and the blazed grating phase. The beam expander 7 is used to expand the light beam.

[0063] In an exemplary embodiment, the optical scanning module includes: a second non-polarization beam splitter 8 , a scanning galvanometer 9 , a scanning lens 10 , a tube lens 11 and an objective lens 12 .

[0064] The expanded fractional-order vortex light sequentially passes through the second non-polarization beam splitter 8, the scanning galvanometer 9, the scanning lens 10, the tube lens 11, the objective lens 12 and the sample 13 to obtain signal return light.

[0065] The signal return light is collected by the objective lens 12, and after passing through the tube lens 11, the scanning lens 10, the scanning galvanometer 9 and the second non-polarizing beam splitter 8, a transmitted signal return light is obtained; the transmitted signal return light is transmitted to the dark field detection module.

[0066] That is to say, the optical scanning module is composed of the second non-polarization beam splitter 8, the scanning galvanometer 9, the scanning lens 10, the tube lens 11, the objective lens 12 and the sample 13 in order according to the light propagation direction.

[0067] The expanded fractional-order vortex light is reflected by the second non-polarizing beam splitter 8 and enters the scanning galvanometer 9, the scanning lens 10 and the tube lens 11. After passing through the scanning lens 10 and the tube lens 11, it fills the entrance pupil diameter of the objective lens 12, and then is focused on the sample 13 by the objective lens 12 and scanned on the sample 13. The signal return light is collected by the objective lens 12 and passes through the tube lens 11, the scanning lens 10 and the scanning galvanometer 9, and is then transmitted to the dark field detection module by the second non-polarizing beam splitter 8.

[0068] Among them, the second non-polarizing beam splitter 8 has the same function as the first non-polarizing beam splitter 5, which will not be repeated here. The scanning galvanometer 9 enables the laser beam to be accurately scanned on a two-dimensional plane. The scanning lens 10 is used to form a focused light spot of uniform size in a plane. The tube lens 11 is usually composed of an optical imaging system and an illumination system, in which the optical imaging system is the core part, which is responsible for receiving light and focusing it onto the objective lens 12, further magnifying and imaging the sample, and the focal length and magnification of the tube lens 11 and the objective lens 12 work together to achieve magnified imaging of the sample.

[0069] In an exemplary embodiment, the dark field detection module includes: an aperture 15, a focusing lens 16, a pinhole 17 and a photomultiplier tube 18;

[0070] The transmitted signal return light sequentially passes through the aperture 15, the focusing lens 16, the pinhole 17 and the photomultiplier tube 18 for dark field detection to obtain a fractional-order scattered dark field image.

[0071] That is to say, the dark field detection module is composed of, in order according to the light propagation direction: an aperture 15 , a focusing lens 16 , a pinhole 17 and a photomultiplier tube 18 .

[0072] Among them, the aperture 15 filters out the approximately annular fractional order reflected light and retains the central solid scattered light. The focusing lens 16 is a gradient refractive index lens, which has the characteristics of end face focusing and imaging, as well as its cylindrical appearance. The pinhole 17 refers to the pore formed by a pair of partitions in the light path. The pinhole 17 is used to realize the tiny point light source in the light path, laser beam filtering, etc. The photomultiplier tube 18 is mainly used to convert weak light signals into electrical signals. The photomultiplier tube 18 is used in optical measuring instruments and spectral analysis instruments. It can measure extremely weak radiation power with a wavelength of 200 to 1200 nanometers in low-level photometry and spectroscopy.

[0073] In an exemplary embodiment, the dark-field confocal microscopy measurement device based on differential fractional-order vortex beam further includes: an axial translation stage 14 .

[0074] The axial translation stage 14 is used to move the sample 13 .

[0075] The present invention adopts a fractional-order vortex light module to perform fractional-order vortex light illumination on the sample. The fractional-order vortex light can be equivalent to the superposition of multiple integer-order vortex components. Multiple orders simultaneously participate in the interaction between light and matter, and produce coherent enhancement and coherent destructive effects between signal lights of each order, which can effectively improve the signal contrast of micro-nanoparticles.

[0076] In another exemplary embodiment of the present invention, Figure 2 As shown, a dark-field confocal microscopy measurement method based on a differential fractional-order vortex beam is provided. The dark-field confocal microscopy measurement method based on a differential fractional-order vortex beam is implemented based on the above-mentioned dark-field confocal microscopy measurement device based on a differential fractional-order vortex beam. The dark-field confocal microscopy measurement method based on a differential fractional-order vortex beam includes.

[0077] S1: Generate a first fractional-order vortex light using a fractional-order vortex light module; the first fractional-order vortex light is light generated by superposition of a first vortex phase and a blazed grating phase.

[0078] S2: Using an optical scanning module to transmit the first fractional-order vortex light to the sample for scanning, and obtaining a first signal return light.

[0079] S3: Perform dark field detection on the first signal return light using a dark field detection module to obtain a first fractional-order scattering dark field image.

[0080] S4: Generate a second fractional-order vortex light using a fractional-order vortex light module; the second fractional-order vortex light is light generated by superposition of the second vortex phase and the blazed grating phase.

[0081] S5 uses an optical scanning module to transmit the second fractional-order vortex light to the sample for scanning to obtain a second signal return light.

[0082] S6: Perform dark field detection on the second signal return light using a dark field detection module to obtain a second fractional-order scattering dark field image.

[0083] S7: Differentiating the first fractional-order scattering dark field image and the second fractional-order scattering dark field image to obtain a differential dark field scattering image.

[0084] S8: Process the differential dark field scattering image to obtain sample defects.

[0085] In an exemplary embodiment, step S1 specifically includes:

[0086] S11: determining a first loading phase distribution of the spatial light modulator in the fractional-order vortex optical module according to the visible light band laser output by the laser.

[0087] S12 generates a first fractional-order vortex light according to the first loading phase distribution.

[0088] The first loading phase distribution is: 1 +Φ.

[0089] Among them, ψ 1 =m 1 φ,m 1 =m 0 +Δm,Φ=2πGx,ψ 1 is the first vortex phase, Φ is the blazed grating phase, m 1 is the first fractional order, φ is the angular polar coordinate of the liquid crystal surface of the spatial light modulator, m 0 is an integer, generally 1, Δm is a constant, 0<Δm<0.5, G is the blazed grating constant, and x is the Cartesian coordinate in the horizontal direction of the liquid crystal surface of the spatial light modulator.

[0090] Similarly, in step S4, it specifically includes.

[0091] S41: Determine a second loading phase distribution of the spatial light modulator in the fractional-order vortex optical module according to the visible light band laser output by the laser.

[0092] S42: Generate a first fractional-order vortex light according to the second loading phase distribution.

[0093] The second loading phase distribution is: 2 +Φ.

[0094] Among them, ψ 2 =m 2 φ,m 2 =m 0 -Δm,Φ=2πGx,ψ 2is the second vortex phase, Φ is the blazed grating phase, m 2 is the second fractional order, φ is the angular polar coordinate of the liquid crystal surface of the spatial light modulator, m 0 is an integer, generally 1, Δm is a constant, 0<Δm<0.5, G is the blazed grating constant, and x is the Cartesian coordinate in the horizontal direction of the liquid crystal surface of the spatial light modulator.

[0095] It should be noted that the transmission direction of the first fractional-order vortex light or the second fractional-order vortex light is determined by the blazed grating constant G. That is, the blazed grating constant G is adjusted to make the output light beam of the spatial light modulator 6 coaxial with the subsequent optical path.

[0096] The present invention can effectively separate the sample surface reflection signal and the interface defect scattering signal, and utilizes the differential results of two fractional-order scattered dark-field images to improve the imaging signal-to-noise ratio and achieve nanometer-level sensitivity defect detection.

[0097] As a possible implementation method, a dark-field confocal microscopy measurement method based on a differential fractional-order vortex beam includes the following steps.

[0098] Step a, laser 1 outputs visible light band laser, half-wave plate 2 and polarizer 3 adjust the polarization state of the visible light band laser to match the spatial light modulator 6, then it is reflected by reflector 4 to the first non-polarizing beam splitter 5, and enters the spatial light modulator 6 after being split by the first non-polarizing beam splitter 5.

[0099] Step b: The first loading phase distribution of the spatial light modulator 6 is: 1 +Φ; where ψ 1 =m 1 φ,m 1 =m 0 +Δm,Φ=2πGx,ψ 1 is the first vortex phase, Φ is the blazed grating phase, m 1 is the first fractional order, φ is the angular polar coordinate of the liquid crystal surface of the spatial light modulator, m 0 is an integer, generally 1, Δm is a constant, 0<Δm<0.5, G is the blazed grating constant, the blazed grating constant is adjusted to make the output light beam of the spatial light modulator 6 coaxial with the subsequent optical path, and x is the Cartesian coordinate in the horizontal direction of the liquid crystal surface of the spatial light modulator. A first fractional-order vortex light is generated according to the first loading phase distribution.

[0100] Step c, after the first fractional-order vortex light is expanded by the beam expander 7, it is reflected by the second non-polarizing beam splitter 8 to the scanning galvanometer 9, and then reflected by the scanning galvanometer 9 to the scanning lens 10, and then focused on the sample 13 through the tube lens 11 and the objective lens 12 and scanned on the sample 13 to obtain the first signal return light;

[0101] Step d: After the first signal return light is collected by the objective lens 12, it passes through the tube lens 11, the scanning lens 10, the scanning galvanometer 9, and the second non-polarizing beam splitter 8, and then is transmitted to the aperture 15 by the second non-polarizing beam splitter 8. The aperture 15 filters out the approximately annular fractional-order reflected light, retains the central solid scattered light, and performs dark field detection by the focusing lens 16, the pinhole 17 and the photomultiplier tube 18 to obtain m 0 +Δm-order scattering dark field image.

[0102] Step e: The second loading phase distribution of the spatial light modulator 6 is: 2 +Φ; where ψ 2 =m 2 φ,m 2 =m 0 -Δm,Φ=2πGx,ψ 1 is the second vortex phase, Φ is the blazed grating phase, m 2 is the second fractional order, φ is the angular polar coordinate of the liquid crystal surface of the spatial light modulator, m 0 is an integer, generally 1, Δm is a constant, 0<Δm<0.5, G is the blazed grating constant, and x is the Cartesian coordinate in the horizontal direction of the liquid crystal surface of the spatial light modulator. A second fractional-order vortex light is generated according to the second loading phase distribution.

[0103] Step f, after the second fractional-order vortex light is expanded by the beam expander 7, it is reflected by the second non-polarizing beam splitter 8 to the scanning galvanometer 9, and then reflected by the scanning galvanometer 9 to the scanning lens 10, and then focused on the sample 13 through the tube lens 11 and the objective lens 12 and scanned on the sample 13 to obtain the second signal return light.

[0104] Step g: After the second signal return light is collected by the objective lens 12, it passes through the tube lens 11, the scanning lens 10, the scanning galvanometer 9, and the second non-polarizing beam splitter 8, and then is transmitted to the aperture 15 by the second non-polarizing beam splitter 8. The aperture 15 filters out the approximately annular fractional-order reflected light, retains the central solid scattered light, and performs dark field detection by the focusing lens 16, the pinhole 17 and the photomultiplier tube 18 to obtain m 0 -Δm-order scattering dark field image.

[0105] Step h: 0 +Δm-order scattering dark field image and m 0 The -Δm-order scattering dark field image is differentiated to obtain a differential dark field scattering image with common mode noise suppression and improved sensitivity.

[0106] Step i: Process the differential dark field scattering image to obtain sample defects.

[0107] The present application also provides an application scenario, which applies the above-mentioned dark-field confocal microscopy measurement method based on differential fractional-order vortex beams. Specifically: The dark-field confocal microscopy measurement method based on differential fractional-order vortex beams provided in this embodiment can be applied in dark-field confocal microscopy measurement scenarios. The dark-field confocal microscopy measurement scenario includes a fractional-order vortex light generation link, an optical scanning link, and a dark-field detection link; different fractional-order vortex lights are generated through a fractional-order vortex light module, and then enter the optical scanning link, and the sample is scanned by different fractional-order vortex lights to obtain different signal return lights, and then different fractional-order scattered dark-field images are obtained through the dark-field detection link, and different fractional-order scattered dark-field images are obtained by differentiating different fractional-order scattered dark-field images, and the differential dark-field scattering image is obtained by processing the differential dark-field scattering image to obtain the sample defect.

[0108] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A dark field confocal microscopy measurement device based on differential fractional-order vortex beam, characterized in that: The dark field confocal microscopy measurement device based on differential fractional-order vortex beam comprises: a fractional-order vortex light module, an optical scanning module, a dark field detection module, a differential dark field scattering image determination module and a defect determination module; The fractional-order vortex light module is used to generate a first fractional-order vortex light and a second fractional-order vortex light; the first fractional-order vortex light is light generated by superposition of a first vortex phase and a blazed grating phase; the second fractional-order vortex light is light generated by superposition of a second vortex phase and a blazed grating phase; The optical scanning module is used to first transmit the first fractional-order vortex light to the sample for scanning to obtain a first signal return light, and then transmit the second fractional-order vortex light to the sample for scanning to obtain a second signal return light; The dark field detection module is used to perform dark field detection on the first signal return light and the second signal return light respectively to obtain a first fractional-order scattering dark field image and a second fractional-order scattering dark field image; The differential dark field scattering image determination module is used to differentiate the first fractional-order scattering dark field image and the second fractional-order scattering dark field image to obtain a differential dark field scattering image; The defect determination module is used to process the differential dark field scattering image to obtain sample defects; The fractional-order vortex optical module comprises: a laser, a half-wave plate, a polarizer, a reflector, a first non-polarizing beam splitter, a spatial light modulator and a beam expander; The laser is used to output visible light band laser, and the visible light band laser passes through the half-wave plate, the polarizer, the reflector, the first non-polarizing beam splitter and the spatial light modulator in sequence to obtain fractional-order vortex light, and the fractional-order vortex light includes: first fractional-order vortex light and second fractional-order vortex light. The fractional-order vortex light is expanded by the beam expander to obtain expanded fractional-order vortex light, and the expanded fractional-order vortex light is transmitted to the optical scanning module; The loading phase distribution of the spatial light modulator is: the vortex phase and the blazed grating phase are superimposed.

2. The dark field confocal microscopy measurement device based on differential fractional-order vortex beam according to claim 1, characterized in that: The optical scanning module comprises: a second non-polarization beam splitter, a scanning galvanometer, a scanning lens, a tube lens and an objective lens; The expanded fractional-order vortex light sequentially passes through the second non-polarization beam splitter, the scanning galvanometer, the scanning lens, the tube lens, the objective lens and the sample to obtain signal return light; The signal return light is collected by the objective lens, and after passing through the tube lens, the scanning lens, the scanning galvanometer and the second non-polarizing beam splitter, a transmitted signal return light is obtained; and the transmitted signal return light is transmitted to the dark field detection module.

3. The dark field confocal microscopy measurement device based on differential fractional-order vortex beam according to claim 2, characterized in that: The dark field detection module includes: an aperture, a focusing lens, a pinhole and a photomultiplier tube; The transmitted signal return light sequentially passes through the aperture, the focusing lens, the pinhole and the photomultiplier tube for dark field detection to obtain a fractional-order scattered dark field image.

4. The dark field confocal microscopy measurement device based on differential fractional-order vortex beam according to claim 1, characterized in that: The dark field confocal microscopy measurement device based on differential fractional-order vortex beam also includes: an axial translation stage; The axial translation stage is used to move the sample.

5. A dark field confocal microscopy measurement method based on differential fractional-order vortex beam, characterized in that: The dark-field confocal microscopy measurement method based on a differential fractional-order vortex beam is implemented based on the dark-field confocal microscopy measurement device based on a differential fractional-order vortex beam as claimed in any one of claims 1 to 4, and the dark-field confocal microscopy measurement method based on a differential fractional-order vortex beam comprises: A first fractional-order vortex light is generated by using a fractional-order vortex light module; the first fractional-order vortex light is light generated by superposition of the first vortex phase and the blazed grating phase; Using an optical scanning module to transmit the first fractional-order vortex light to a sample for scanning, to obtain a first signal return light; Performing dark field detection on the first signal return light using a dark field detection module to obtain a first fractional-order scattering dark field image; A second fractional-order vortex light is generated by using a fractional-order vortex light module; the second fractional-order vortex light is light generated by superposition of the second vortex phase and the blazed grating phase; Using an optical scanning module to transmit the second fractional-order vortex light to the sample for scanning, to obtain a second signal return light; Performing dark field detection on the second signal return light using a dark field detection module to obtain a second fractional-order scattering dark field image; Differentiating the first fractional-order scattering dark-field image and the second fractional-order scattering dark-field image to obtain a differential dark-field scattering image; Processing the differential dark field scattering image to obtain sample defects; The method of generating the first fractional-order vortex light by using the fractional-order vortex light module specifically includes: Determining a first loading phase distribution of a spatial light modulator in the fractional-order vortex optical module according to the visible light band laser output by the laser; generating a first fractional-order vortex light according to the first loading phase distribution; The first loading phase distribution is: ; in, , , , is the first vortex phase, is the blazed grating phase, is the first fractional order, is the angular polar coordinate of the liquid crystal surface of the spatial light modulator, is an integer, is a constant, , is the blazed grating constant, is the Cartesian coordinate in the horizontal direction of the liquid crystal surface of the spatial light modulator; The method of generating the second fractional-order vortex light by using the fractional-order vortex light module specifically includes: Determining a second loading phase distribution of the spatial light modulator in the fractional-order vortex optical module according to the visible light band laser output by the laser; generating a second fractional-order vortex light according to the second loading phase distribution; The second loading phase distribution is: ; in, , , , is the second vortex phase, is the blazed grating phase, is the second fractional order, is the angular polar coordinate of the liquid crystal surface of the spatial light modulator, is an integer, is a constant, , is the blazed grating constant, is the Cartesian coordinate in the horizontal direction of the liquid crystal surface of the spatial light modulator.

6. The dark field confocal microscopy measurement method based on differential fractional-order vortex beam according to claim 5, characterized in that: The transmission direction of the first fractional-order vortex light or the second fractional-order vortex light is determined by the blazed grating constant.

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