Vortex dichroism dark-field confocal microscopy measurement device based on spiral transformation

Abstract

The present application discloses a vortex dichroism dark field confocal microscopy measurement device based on spiral transformation, which relates to the field of optical precision measurement technology. An opposite order vortex beam generating module is used to generate a mixed vortex beam, a sample scanning module is used to irradiate a scanning position of a sample to be measured with the mixed vortex beam, and obtain a sample reflected beam, a spiral transformation module is used to spatially separate the sample reflected beam, and obtain a spatially separated beam, a multi-order detection module is used to detect the spatially separated beam, and obtain the vortex dichroism signal intensity at the scanning position. When there is no defect at the scanning position of the sample to be measured, the vortex dichroism signal intensity is 0, and when there is a defect at the scanning position of the sample to be measured, the vortex dichroism signal intensity is not 0, and the positive and negative nature of the vortex dichroism signal intensity corresponds to the left-handed chirality and the right-handed chirality of the defect, respectively, so that the chiral characteristics of defects between layers of three-dimensional integrated circuits can be explored.

Description

Technical Field

[0001] The present application relates to the technical field of optical precision measurement, and in particular to a vortex dichroism dark field confocal microscopic measurement device based on spiral transformation demodulation of orbital angular momentum spectrum. Background Art

[0002] Interlayer defects (such as holes and stacking faults) of semiconductor three-dimensional integrated circuits can easily lead to a decrease in the electrical performance and life of the three-dimensional integrated circuits. Accurate detection of interlayer defects can ensure the product yield of the three-dimensional integrated circuits.

[0003] Confocal microscopy measurement technology can be used for nondestructive detection of three-dimensional integrated circuit defects due to its three-dimensional tomography capability. Among them, dark-field confocal microscopy measurement technology has the advantages of good optical tomography capability, high imaging resolution, and high imaging contrast brought by dark background, and has become an important means of nondestructive detection of three-dimensional integrated circuit defects. However, traditional optical dark-field confocal microscopy measurement technology has a low response rate to tiny scale defects, and is limited by the dimension of information acquisition. It can only detect geometric defects (such as scratches, pits, etc.), and cannot obtain more defect characteristic information, resulting in insufficient accuracy in defect judgment.

[0004] Therefore, how to expand the detectable defect characteristics and explore the chiral characteristics of defects between layers of three-dimensional integrated circuits is an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0005] The purpose of the present application is to provide a vortex dichroism dark field confocal microscopy measurement device based on spiral transformation, which can explore the chiral characteristics of interlayer defects in three-dimensional integrated circuits.

[0006] To achieve the above objectives, this application provides the following solutions:

[0007] The present application provides a vortex dichroism dark field confocal microscopy measurement device based on spiral transformation, and the vortex dichroism dark field confocal microscopy measurement device based on spiral transformation includes:

[0008] An opposite-order vortex beam generating module is used to generate a mixed vortex beam; the mixed vortex beam includes a positive m-order orbital angular momentum and a negative m-order orbital angular momentum, where m is a constant;

[0009] A sample scanning module, used for irradiating a scanning position of a sample to be tested with the mixed vortex light beam to obtain a sample reflected light beam at the scanning position; the sample to be tested is a three-dimensional integrated circuit; the sample reflected light beam includes positive m-order orbital angular momentum and negative m-order orbital angular momentum;

[0010] A spiral transformation module is used to spatially separate the sample reflected light beam to obtain a spatially separated light beam; the spatially separated light beam includes a first light beam corresponding to a positive m-order orbital angular momentum and a second light beam corresponding to a negative m-order orbital angular momentum, and the positions of the first light beam and the second light beam are separated;

[0011] The multi-stage detection module is used to detect the spatially separated light beam to obtain the vortex dichroism signal intensity of the scanning position; the vortex dichroism signal intensity is used to characterize whether the scanning position has a defect and the chiral characteristics of the defect when there is a defect.

[0012] Optionally, the opposite-order vortex beam generating module includes: a laser, a half-wave plate, a first polarizer, a first non-polarizing beam splitter and a first liquid crystal spatial light modulator arranged in sequence according to the propagation direction of light; the first liquid crystal spatial light modulator is used to phase modulate the reflected light beam of the first non-polarizing beam splitter to obtain a mixed vortex beam; the mixed vortex beam is transmitted to the sample scanning module through the first non-polarizing beam splitter.

[0013] Optionally, the sample scanning module includes: a beam expander, an aperture stop, a second non-polarizing beam splitter and an objective lens arranged in sequence according to the direction of light propagation; the objective lens is used to focus the transmitted light beam of the second non-polarizing beam splitter to the scanning position of the sample to be measured, so as to obtain the sample reflected light beam at the scanning position; the sample reflected light beam is transmitted through the objective lens and then reflected through the second non-polarizing beam splitter to the spiral transformation module.

[0014] Optionally, the sample scanning module further includes: a three-dimensional displacement stage; the sample to be tested is located on the three-dimensional displacement stage; the three-dimensional displacement stage is used to drive the sample to be tested to move and adjust the scanning position of the sample to be tested.

[0015] Optionally, the spiral transformation module includes: a second polarizer, a third non-polarizing beam splitter, a second liquid crystal spatial light modulator, a fourth non-polarizing beam splitter and a third liquid crystal spatial light modulator arranged in sequence according to the propagation direction of light; the second liquid crystal spatial light modulator is used to phase modulate the transmitted light beam of the third non-polarizing beam splitter to obtain a preliminary separated light beam; the third liquid crystal spatial light modulator is used to phase modulate the transmitted light beam of the fourth non-polarizing beam splitter to obtain a spatially separated light beam; the spatially separated light beam is reflected to the multi-order detection module via the fourth non-polarizing beam splitter.

[0016] Optionally, the multi-order detection module includes: a focusing lens, a slit array and a linear array photomultiplier tube arranged in sequence according to the direction of light propagation; the focusing lens is used to focus the spatially separated light beam to obtain a focused light beam; the slit array is used to filter out the out-of-focus background in the focused light beam to obtain a filtered light beam; the linear array photomultiplier tube is used to perform photoelectric conversion on the filtered light beam to obtain an electrical signal, and process the electrical signal to obtain the vortex dichroism signal intensity at the scanning position.

[0017] Optionally, a first phase distribution is loaded on the first liquid crystal spatial light modulator;

[0018] The first phase distribution is:

[0019]

[0020] in, is the first phase distribution, is the angular coordinate of the photosensitive surface of the first liquid crystal spatial light modulator; k is a constant; and π is the pi.

[0021] Optionally, a second phase distribution is loaded on the second liquid crystal spatial light modulator;

[0022] The second phase distribution is:

[0023]

[0024] Among them, Φ 2 (x, y) is the second phase distribution, x, y are the x-coordinate and y-coordinate of the liquid crystal surface of the second liquid crystal spatial light modulator respectively; π is the circumference; d is the first debugging parameter; λ is the wavelength of the illumination light; f is the lens phase focal length; p is the second debugging parameter; n is a constant, n=-1, 0, 1; b n is the third debugging parameter; θ is the angle, θ=2πd / f; a n It is the fourth debugging parameter.

[0025] Optionally, a third phase distribution is loaded on the third liquid crystal spatial light modulator;

[0026] The third phase distribution is:

[0027]

[0028] Among them, Φ 3 (u, v) is the third phase distribution, u, v are the x-coordinate and y-coordinate of the liquid crystal surface of the third liquid crystal spatial light modulator respectively; n is a constant, n=-1, 0, 1; π is the pi; d is the first debugging parameter; p is the second debugging parameter; λ is the wavelength of the illumination light; f is the lens phase focal length.

[0029] Optionally, the electrical signal is processed to obtain the vortex dichroism signal intensity at the scanning position, specifically including: superimposing the signal intensity of each signal channel in the first region of the electrical signal to obtain a first superimposed signal intensity, superimposing the signal intensity of each signal channel in the second region of the electrical signal to obtain a second superimposed signal intensity, and calculating the difference between the first superimposed signal intensity and the second superimposed signal intensity to obtain the vortex dichroism signal intensity at the scanning position; wherein the first region is a region composed of signal channels corresponding to the first light beam, and the second region is a region composed of signal channels corresponding to the second light beam.

[0030] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0031] The present application provides a vortex dichroism dark field confocal microscopy measurement device based on spiral transformation, wherein an opposite order vortex beam generation module is used to generate a mixed vortex beam, a sample scanning module is used to use the mixed vortex beam to irradiate a scanning position of a sample to be measured, and obtain a sample reflected beam at the scanning position, the sample to be measured is a three-dimensional integrated circuit, the spiral transformation module is used to perform spatial separation on the sample reflected beam, and obtain a spatially separated beam, the multi-order detection module is used to detect the spatially separated beam, and obtain the vortex dichroism signal intensity at the scanning position, when the scanning position of the sample to be measured is free of defects, the vortex dichroism signal The intensity is 0. When there is a defect at the scanning position of the sample to be tested, the vortex dichroism signal intensity is not 0, and the positive and negative values ​​of the vortex dichroism signal intensity correspond to the chiral characteristics of the defect. The chiral characteristics are introduced from biological concepts and are used to measure the asymmetry of the defect. When the vortex dichroism signal intensity is positive, the defect is right-handed, and when the vortex dichroism signal intensity is negative, the defect is left-handed. Therefore, by determining the vortex dichroism signal intensity at the scanning position, the defect detection and the characterization of the chiral characteristics of the defect when there is a defect can be achieved, thereby exploring the chiral characteristics of defects between layers of three-dimensional integrated circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 This is a schematic structural diagram of the vortex dichroism dark-field confocal microscopy measurement device based on spiral transformation provided in Example 1 of the present application.

[0034] Explanation of symbols:

[0035] 1-laser; 2-half-wave plate; 3-first polarizer; 4-first non-polarizing beam splitter; 5-first liquid crystal spatial light modulator; 6-beam expander; 7-aperture diaphragm; 8-second non-polarizing beam splitter; 9-objective lens; 10-sample to be measured; 11-three-dimensional translation stage; 12-second polarizer; 13-third non-polarizing beam splitter; 14-second liquid crystal spatial light modulator; 15-fourth non-polarizing beam splitter; 16-third liquid crystal spatial light modulator; 17-focusing lens; 18-slit array; 19-linear array photomultiplier tube. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0037] Example 1

[0038] like Figure 1 As shown, this embodiment provides a vortex dichroism dark field confocal microscopy measurement device based on spiral transformation, and the vortex dichroism dark field confocal microscopy measurement device based on spiral transformation includes:

[0039] The opposite order vortex beam generating module is used to generate a mixed vortex beam, wherein the mixed vortex beam includes a positive m-order orbital angular momentum and a negative m-order orbital angular momentum, where m is a constant.

[0040] The sample scanning module is used to irradiate the scanning position of the sample to be tested 10 with a mixed vortex beam to obtain a sample reflected beam at the scanning position. The sample to be tested is a three-dimensional integrated circuit, and the sample reflected beam includes positive m-order orbital angular momentum and negative m-order orbital angular momentum.

[0041] The spiral transformation module is used to spatially separate the sample reflected light beam to obtain a spatially separated light beam, which includes a first light beam corresponding to the positive m-order orbital angular momentum and a second light beam corresponding to the negative m-order orbital angular momentum, and the positions of the first light beam and the second light beam are separated.

[0042] The multi-stage detection module is used to detect the spatially separated light beams to obtain the vortex dichroism signal intensity at the scanning position. The vortex dichroism signal intensity is used to characterize whether there is a defect at the scanning position and the chiral characteristics of the defect when there is a defect.

[0043] In this embodiment, the opposite-order vortex beam generating module is used to generate a mixed vortex beam containing orbital angular momentum of opposite orders (i.e., positive m-order and negative m-order). Since the mixed vortex beam is used to irradiate the sample 10 to be tested, the mixed vortex beam can be called a mixed vortex illumination beam. The mixed vortex beam includes positive m-order orbital angular momentum and negative m-order orbital angular momentum, where m is a constant.

[0044] Specifically, the opposite-order vortex beam generating module includes: a laser 1, a half-wave plate 2, a first polarizer 3, a first non-polarizing beam splitter 4 and a first liquid crystal spatial light modulator 5 which are arranged in sequence according to the propagation direction of the light.

[0045] The laser 1 is used to output parallel coherent laser light.

[0046] The half-wave plate 2 has the function of rotating polarized light, and the polarizer has the function of shielding and transmitting incident light. The half-wave plate 2 and the first polarizer 3 cooperate to adjust the polarization state of the parallel coherent laser output by the laser 1 so that the output light beam of the first polarizer 3 matches the first liquid crystal spatial light modulator 5.

[0047] The first non-polarization beam splitter 4 is used to split the outgoing light beam of the first polarizer 3 to obtain a transmitted light beam and a reflected light beam, and the reflected light beam is incident on the first liquid crystal spatial light modulator 5 .

[0048] The first liquid crystal spatial light modulator 5 is used to phase modulate the reflected light beam of the first non-polarizing beam splitter 4 , generate a mixed vortex light beam containing positive and negative m-order orbital angular momentum through phase modulation, and input the mixed vortex light beam into the first non-polarizing beam splitter 4 .

[0049] The first liquid crystal spatial light modulator 5 is loaded with a first phase distribution. By loading the first phase distribution, the first liquid crystal spatial light modulator 5 has the function of generating a mixed vortex light beam containing positive and negative m-order orbital angular momentum through phase modulation, that is, the vortex light beam emitted by the first liquid crystal spatial light modulator 5 contains both positive and negative m-order orbital angular momentum.

[0050] The first phase distribution is:

[0051]

[0052] in, is the first phase distribution, is the angular coordinate of the photosensitive surface of the first liquid crystal spatial light modulator 5; k is a constant, k=0, 1, ...; π is the pi; m is a constant, as an example, m=1, 2, ..., 10.

[0053] The first non-polarizing beam splitter 4 is also used to split the mixed vortex beam output by the first liquid crystal spatial light modulator 5 to obtain a transmitted beam and a reflected beam. The transmitted beam is incident on the sample scanning module, that is, the mixed vortex beam is transmitted to the sample scanning module through the first non-polarizing beam splitter 4.

[0054] In this embodiment, the sample scanning module is used to transmit the mixed vortex light beam to the sample to be tested 10, and use the mixed vortex light beam to irradiate the scanning position of the sample to be tested 10 to obtain a sample reflected light beam at the scanning position. The sample reflected light beam carries the defect information of the scanning position, so it can be called sample signal return light. The sample reflected light beam includes positive m-order orbital angular momentum and negative m-order orbital angular momentum.

[0055] Specifically, the sample scanning module includes: a beam expander 6, an aperture stop 7, a second non-polarizing beam splitter 8 and an objective lens 9 which are arranged in sequence according to the light propagation direction.

[0056] The beam expander 6 is used to expand the mixed vortex light beam to obtain an expanded light beam. The beam expansion multiple of the beam expander 6 can be 3-5 times.

[0057] The aperture stop 7 is used to adjust the diameter of the light beam after beam expansion, so that the diameter of the light beam emitted from the aperture stop 7 matches the entrance pupil diameter of the objective lens 9.

[0058] The second non-polarization beam splitter 8 is used to split the outgoing light beam of the aperture stop 7 to obtain a transmitted light beam and a reflected light beam, and the transmitted light beam is incident on the objective lens 9 .

[0059] The objective lens 9 is used to focus the transmitted light beam of the second non-polarization beam splitter 8 to the scanning position of the sample 10 to be measured, so as to obtain the sample reflected light beam returned from the scanning position.

[0060] The objective lens 9 is also used to collect the sample reflected light beam and make the sample reflected light beam incident on the second non-polarizing beam splitter 8. The second non-polarizing beam splitter 8 is also used to split the output light beam of the objective lens 9 to obtain a transmitted light beam and a reflected light beam. The reflected light beam is incident on the sample scanning module, that is, the sample reflected light beam is transmitted through the objective lens 9 and then reflected through the second non-polarizing beam splitter 8 to the spiral transformation module.

[0061] In order to adjust the scanning position, the sample scanning module of this embodiment also includes: a three-dimensional displacement stage 11. The sample 10 to be tested is located on the three-dimensional displacement stage 11. The three-dimensional displacement stage 11 is moved by controlling the three-dimensional displacement stage 11. The three-dimensional displacement stage 11 is used to drive the sample 10 to be tested to move and adjust the scanning position of the sample 10 to be tested, so that defects at all positions of the sample 10 to be tested can be detected.

[0062] In this embodiment, the spiral transformation module is used to use a cascaded liquid crystal spatial light modulator to spatially separate the sample reflected light beams containing orbital angular momentum of different orders (i.e., positive m-order and negative m-order) to obtain spatially separated light beams. The spatially separated light beams include a first light beam corresponding to the positive m-order orbital angular momentum and a second light beam corresponding to the negative m-order orbital angular momentum, and the positions of the first light beam and the second light beam are separated.

[0063] Specifically, the spiral transformation module includes: a second polarizer 12, a third non-polarization beam splitter 13, a second liquid crystal spatial light modulator 14, a fourth non-polarization beam splitter 15 and a third liquid crystal spatial light modulator 16 which are arranged in sequence according to the light propagation direction.

[0064] The second polarizer 12 is used to adjust the polarization state of the sample reflected light beam so that the polarization state of the output light beam of the second polarizer 12 matches the second liquid crystal spatial light modulator 14 and the third liquid crystal spatial light modulator 16. The second liquid crystal spatial light modulator 14 and the third liquid crystal spatial light modulator 16 are used to spatially separate the vortex light components (i.e., the first light beam and the second light beam) corresponding to the positive and negative m-order orbital angular momentum in the sample reflected light beam.

[0065] The third non-polarization beam splitter 13 is used to split the outgoing light beam of the second polarizer 12 to obtain a transmitted light beam and a reflected light beam, and the transmitted light beam is incident on the second liquid crystal spatial light modulator 14 .

[0066] The second liquid crystal spatial light modulator 14 is used to phase modulate the transmitted light beam of the third non-polarizing beam splitter 13. The transmitted light beam containing orbital angular momentum of different orders is spatially separated through phase modulation, and is shaped into a seriously distorted long strip distribution light beam to obtain a preliminary separated light beam. In the preliminary separated light beam, each order of orbital angular momentum corresponds to a long strip light beam, and the long strip light beams corresponding to multiple orders of orbital angular momentum are parallel, that is, the first light beam and the second light beam are both long strip light beams.

[0067] The second liquid crystal spatial light modulator 14 is loaded with a second phase distribution, and the second phase distribution is:

[0068]

[0069] Among them, Φ 2 (x, y) is the second phase distribution, x, y are the x-coordinate and y-coordinate of the liquid crystal surface of the second liquid crystal spatial light modulator 14, respectively; π is the circumference of a circle; d is the first debugging parameter; λ is the wavelength of the illumination light, i.e., the wavelength of the parallel coherent laser light emitted by the laser 1; the last item is the lens phase term, f is the lens phase focal length; p is the second debugging parameter; n is a constant, n=-1, 0, 1; b n is the third debugging parameter, each n corresponds to a b n, 1 n <2; θ is the angle, θ=2πd / f; a n is the fourth debugging parameter. As an example, a -1 =-π / 2, a 0 =0,a 1 =π / 2.

[0070] The spatial positions of the vortex light components after separation corresponding to the positive and negative m-order orbital angular momentums are determined by the first debugging parameter, the second debugging parameter, the third debugging parameter and the fourth debugging parameter.

[0071] The third non-polarization beam splitter 13 is further used to split the preliminary separated light beam output by the second liquid crystal spatial light modulator 14 to obtain a transmitted light beam and a reflected light beam, and the reflected light beam is incident on the fourth non-polarization beam splitter 15 .

[0072] The fourth non-polarization beam splitter 15 is used for splitting the reflected light beam of the third non-polarization beam splitter 13 to obtain a reflected light beam and a transmitted light beam, and the transmitted light beam is incident on the third liquid crystal spatial light modulator 16 .

[0073] The third liquid crystal spatial light modulator 16 is used to phase modulate the transmitted light beam of the fourth non-polarizing beam splitter 15, and through phase modulation, the seriously distorted long strip distribution light beam is shaped into a distortion-free long strip distribution light beam to obtain a spatially separated light beam, and the spatially separated light beam is incident on the fourth non-polarizing beam splitter 15.

[0074] The third phase distribution is loaded on the third liquid crystal spatial light modulator 16, and the third phase distribution is:

[0075]

[0076] Among them, Φ 3 (u, v) is the third phase distribution, u, v are the x-coordinate and y-coordinate of the liquid crystal surface of the third liquid crystal spatial light modulator 16 respectively; n is a constant, n = -1, 0, 1; π is the pi; d is the first debugging parameter; p is the second debugging parameter; λ is the wavelength of the illumination light; f is the lens phase focal length; rect(A) is a rectangular function, if the absolute value of A is not greater than 0.5, then rect(A) = 1, if the absolute value of A is greater than 0.5, then rect(A) = 0, A is a variable.

[0077] The fourth non-polarizing beam splitter 15 is also used to split the spatially separated light beam to obtain a reflected light beam and a transmitted light beam. The reflected light beam is incident on the multi-order detection module, that is, the spatially separated light beam is reflected to the multi-order detection module by the fourth non-polarizing beam splitter 15 .

[0078] ​In this embodiment, the multi-order detection module is used to detect the spatially separated light beam, specifically, to detect the intensities of the vortex light components corresponding to the multi-order (i.e., positive and negative m-order) orbital angular momentum in the spatially separated light beam in a confocal mode, and simultaneously record the intensities of the vortex light components corresponding to the multi-order orbital angular momentum to obtain the vortex dichroism signal intensity at the scanning position. The vortex dichroism signal intensity is used to characterize whether the scanning position has a defect and the defect characteristics when there is a defect.

[0079] Specifically, the multi-stage detection module includes: a focusing lens 17, a slit array 18 and a linear array photomultiplier tube 19 which are arranged in sequence according to the light propagation direction.

[0080] The focusing lens 17 is used to focus the spatially separated light beams to obtain focused light beams.

[0081] The slit array 18 is used to filter out the out-of-focus background in the focused light beam to obtain a filtered light beam. The spatial position of the slit array 18 is designed to correspond to the spatial position of the spatially separated light beam, and the slit width is 50-100 μm.

[0082] The linear array photomultiplier tube 19 is used to perform photoelectric conversion on the filtered light beam to obtain an electrical signal, and process the electrical signal to obtain the vortex dichroism signal intensity at the scanning position.

[0083] The electrical signal includes multiple signal channels. Since the positions of the first and second beams in the spatially separated beams are separated, the signal channels corresponding to the first and second beams are different. At this time, there are two signal channel areas in the electrical signal whose signal intensity is greater than a preset value (the preset value is the background intensity). One signal channel area corresponds to the first beam, and the other signal channel area corresponds to the second beam. The signal intensities of each signal channel within each signal channel area are superimposed, and then the two superposition results are subtracted. The signal intensities of the two brightest areas are superimposed and subtracted, and the vortex dichroism signal intensity at the scanning position can be obtained. Then, the electrical signal is processed to obtain the vortex dichroism signal intensity at the scanning position, specifically including: superimposing the signal intensity of each signal channel in the first area of ​​the electrical signal to obtain a first superimposed signal intensity, superimposing the signal intensity of each signal channel in the second area of ​​the electrical signal to obtain a second superimposed signal intensity, calculating the difference between the first superimposed signal intensity and the second superimposed signal intensity, and obtaining the vortex dichroism signal intensity at the scanning position. Among them, the first area is the area composed of the signal channels corresponding to the first beam, and the second area is the area composed of the signal channels corresponding to the second beam.

[0084] In this embodiment, the illumination light (i.e., the parallel coherent laser light emitted by the laser 1) is modulated by the first liquid crystal spatial light modulator 5 to generate a mixed vortex light beam containing orbital angular momentum of opposite order, and the mixed vortex light beam is used to illuminate the scanning position of the sample to be tested 10 to illuminate the scanning position to obtain a sample reflection light beam, and the sample reflection light beam is demodulated by cascading the second liquid crystal spatial light modulator 14 and the third liquid crystal spatial light modulator 16 to quickly extract the intensity of the spiral spectrum components of multiple orders to obtain a spatially separated light beam, and the spatially separated light beam is detected to obtain the vortex dichroism signal intensity of the scanning position. Since the surface reflection information of the sample to be tested does not show vortex dichroism, and the interlayer defect information of the sample to be tested is prone to generate vortex dichroism signals due to its structural disorder, showing vortex dichroism, the surface reflection information and the interlayer defect information can be separated, and the presence or absence of defects is determined based on the vortex dichroism signal intensity, and the chiral characteristics of the defects are determined when defects are present, which is conducive to accurate defect detection of three-dimensional integrated circuits.

[0085] The working process of the dark field confocal microscopy measurement device of this embodiment includes:

[0086] (1) The laser 1 outputs parallel coherent laser light in the visible light band. After the polarization state of the parallel coherent laser light is adjusted by the half-wave plate 2 and the first polarizer 3, the parallel coherent laser light is reflected by the first non-polarizing beam splitter 4 to the first liquid crystal spatial light modulator 5, and phase modulated by the first liquid crystal spatial light modulator 5 to obtain a mixed vortex light beam.

[0087] (2) The mixed vortex light beam is transmitted to the beam expander 6 through the first non-polarizing beam splitter 4. After the beam is expanded by the beam expander 6 and the beam diameter is adjusted by the aperture diaphragm 7, the mixed vortex light beam is transmitted to the objective lens 9 through the second non-polarizing beam splitter 8. The mixed vortex light beam is focused to the scanning position of the sample 10 to obtain the sample reflected light beam. The sample 10 to be tested is controlled to move by the three-dimensional translation stage 11 to achieve two-dimensional imaging or three-dimensional imaging.

[0088] (3) The reflected light beam of the sample is transmitted through the objective lens 9, and then reflected through the second non-polarizing beam splitter 8 to the second polarizer 12. After the polarization state is adjusted by the second polarizer 12, the reflected light beam is transmitted through the third non-polarizing beam splitter 13 to the second liquid crystal spatial light modulator 14. After the phase is modulated by the second liquid crystal spatial light modulator 14, a preliminary separated light beam is obtained.

[0089] (4) After the preliminary separated light beam is reflected by the third non-polarizing beam splitter 13, it is transmitted to the third liquid crystal spatial light modulator 16 through the fourth non-polarizing beam splitter 15, and is phase modulated by the third liquid crystal spatial light modulator 16 to obtain a spatially separated light beam.

[0090] (5) The spatially separated light beam is reflected by the fourth non-polarizing beam splitter 15 to the focusing lens 17, and then is focused by the focusing lens 17 and filtered out of focus background by the slit array 18 before being incident on the linear array photomultiplier tube 19, which detects and records the light beam to obtain the vortex dichroism signal intensity.

[0091] Traditional bright field confocal measurement and dark field confocal measurement can only obtain the three-dimensional position of the sample 10 to be tested and the defects on the sample 10 to be tested. The present embodiment describes the structure of the defects and the sample 10 to be tested with the vortex dichroism signal intensity (i.e., the difference in signal intensity between the first light beam and the second light beam corresponding to the positive and negative m-order orbital angular momentum, respectively). Where there are no defects and micro-nano structures, the vortex dichroism signal intensity is 0. Where there are defects, the vortex dichroism signal intensity is not 0. Moreover, the positive and negative signs of the vortex dichroism signal intensity correspond to the left-handed and right-handed chirality of the defects, respectively, with positive corresponding to right-handed chirality and negative corresponding to left-handed chirality. Therefore, the dark field confocal characterization capability and scope can be expanded to realize the characterization of the chiral characteristics of the defects. Subsequently, the defects and chiral characteristics can be used for identification and classification, thereby realizing micro-nano structure identification and defect classification of the sample 10 to be tested.

[0092] This embodiment utilizes the phase design of the first liquid crystal spatial light modulator 5 to achieve simultaneous illumination of positive and negative order vortex light, and simultaneously utilizes spiral transformation to separate the vortex light components of each order in space, and utilizes the slit array 18 and the linear array photomultiplier tube 19 to achieve simultaneous detection of the separated vortex light components of each order, thereby improving the measurement rate of vortex dichroism, and effectively avoiding the influence of reduced stability caused by multiple measurements, thereby achieving high-reliability measurement of vortex dichroism.

[0093] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, 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 this application.

Claims

1. A vortex dichroism dark field confocal microscopy measurement device based on spiral transformation, characterized in that: The vortex dichroism dark field confocal microscopy measurement device based on spiral transformation comprises: An opposite-order vortex beam generating module is used to generate a mixed vortex beam; the mixed vortex beam includes a positive m-order orbital angular momentum and a negative m-order orbital angular momentum, where m is a constant; A sample scanning module, used for irradiating a scanning position of a sample to be tested with the mixed vortex light beam to obtain a sample reflected light beam at the scanning position; the sample to be tested is a three-dimensional integrated circuit; the sample reflected light beam includes positive m-order orbital angular momentum and negative m-order orbital angular momentum; A spiral transformation module is used to spatially separate the sample reflected light beam to obtain a spatially separated light beam; the spatially separated light beam includes a first light beam corresponding to a positive m-order orbital angular momentum and a second light beam corresponding to a negative m-order orbital angular momentum, and the positions of the first light beam and the second light beam are separated; A multi-stage detection module, used to detect the spatially separated light beam to obtain the vortex dichroism signal intensity at the scanning position; the vortex dichroism signal intensity is used to characterize whether the scanning position has a defect and the chiral characteristics of the defect when the defect exists; The opposite-order vortex beam generating module comprises: a laser, a half-wave plate, a first polarizer, a first non-polarizing beam splitter and a first liquid crystal spatial light modulator arranged in sequence according to the propagation direction of the light; the first liquid crystal spatial light modulator is used to phase modulate the reflected light beam of the first non-polarizing beam splitter to obtain a mixed vortex beam; the mixed vortex beam is transmitted to the sample scanning module through the first non-polarizing beam splitter; The spiral transformation module includes: a second polarizer, a third non-polarization beam splitter, a second liquid crystal spatial light modulator, a fourth non-polarization beam splitter and a third liquid crystal spatial light modulator arranged in sequence according to the propagation direction of light; the second liquid crystal spatial light modulator is used to phase modulate the transmitted light beam of the third non-polarization beam splitter to obtain a preliminary separated light beam; the third liquid crystal spatial light modulator is used to phase modulate the transmitted light beam of the fourth non-polarization beam splitter to obtain a spatially separated light beam; the spatially separated light beam is reflected to the multi-order detection module via the fourth non-polarization beam splitter; The multi-order detection module includes: a focusing lens, a slit array and a linear array photomultiplier tube arranged in sequence according to the propagation direction of light; the focusing lens is used to focus the spatially separated light beam to obtain a focused light beam; the slit array is used to filter out the out-of-focus background in the focused light beam to obtain a filtered light beam; the linear array photomultiplier tube is used to perform photoelectric conversion on the filtered light beam to obtain an electrical signal, and process the electrical signal to obtain the vortex dichroism signal intensity at the scanning position.

2. The vortex dichroism dark field confocal microscopy measurement device based on spiral transformation according to claim 1, characterized in that: The sample scanning module includes: a beam expander, an aperture stop, a second non-polarizing beam splitter and an objective lens arranged in sequence according to the propagation direction of light; the objective lens is used to focus the transmitted light beam of the second non-polarizing beam splitter to the scanning position of the sample to be measured, so as to obtain the sample reflected light beam at the scanning position; the sample reflected light beam is transmitted by the objective lens and then reflected by the second non-polarizing beam splitter to the spiral transformation module.

3. The vortex dichroism dark field confocal microscopy measurement device based on spiral transformation according to claim 2, characterized in that: The sample scanning module further includes: a three-dimensional displacement platform; the sample to be tested is located on the three-dimensional displacement platform; the three-dimensional displacement platform is used to drive the sample to be tested to move and adjust the scanning position of the sample to be tested.

4. The vortex dichroism dark field confocal microscopy measurement device based on spiral transformation according to claim 1, characterized in that: A first phase distribution is loaded on the first liquid crystal spatial light modulator; The first phase distribution is: ； in, is the first phase distribution, is the angular coordinate of the photosensitive surface of the first liquid crystal spatial light modulator; k is a constant; is the ratio of pi.

5. The vortex dichroism dark field confocal microscopy measurement device based on spiral transformation according to claim 1, characterized in that: A second phase distribution is loaded on the second liquid crystal spatial light modulator; The second phase distribution is: ； in, is the second phase distribution, are respectively the x-coordinate and the y-coordinate of the liquid crystal plane of the second liquid crystal spatial light modulator; is the ratio of pi; is the first debugging parameter; is the wavelength of illumination light; is the lens phase focal length; is the second debugging parameter; is a constant, =-1, 0, 1; is the third debugging parameter; is the angle, ; It is the fourth debugging parameter.

6. The vortex dichroism dark field confocal microscopy measurement device based on spiral transformation according to claim 1, characterized in that: A third phase distribution is loaded on the third liquid crystal spatial light modulator; The third phase distribution is: ； in, is the third phase distribution, are respectively the x-coordinate and the y-coordinate of the liquid crystal plane of the third liquid crystal spatial light modulator; is a constant, =-1, 0, 1; is the ratio of pi; is the first debugging parameter; is the second debugging parameter; is the wavelength of illumination light; is the phase focal length of the lens.

7. The vortex dichroism dark field confocal microscopy measurement device based on spiral transformation according to claim 1, characterized in that: The electrical signal is processed to obtain the vortex dichroism signal intensity at the scanning position, specifically comprising: superimposing the signal intensity of each signal channel in the first area of ​​the electrical signal to obtain a first superimposed signal intensity, superimposing the signal intensity of each signal channel in the second area of ​​the electrical signal to obtain a second superimposed signal intensity, and calculating the difference between the first superimposed signal intensity and the second superimposed signal intensity to obtain the vortex dichroism signal intensity at the scanning position; wherein the first area is an area composed of signal channels corresponding to the first light beam, and the second area is an area composed of signal channels corresponding to the second light beam.

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