Wafer detection method based on Brillouin spectrum and related equipment

Abstract

The invention discloses a wafer detection method based on a Brillouin spectrum and related equipment, and relates to the technical field of wafer detection, and the wafer detection method based on the Brillouin spectrum comprises the following steps: obtaining an actually measured full width at half maximum and an actually measured frequency shift according to Brillouin spectrum information; and calculating lattice arrangement regularity according to the actually measured full width at half maximum, the actually measured frequency shift, the standard full width at half maximum and the standard frequency shift, wherein the lattice arrangement regularity is used for representing whether a crystal defect exists at the corresponding detection position point of the wafer. According to the wafer detection method based on the Brillouin spectrum, the problem that the existing wafer detection technology cannot realize lossless, rapid and accurate detection of the crystal defects of the wafer can be solved, and the crystal defects of the wafer can be detected losslessly, rapidly and accurately.

Description

Technical Field

[0001] The invention belongs to the technical field of wafer detection, and in particular relates to a wafer detection method based on Brillouin spectroscopy and related equipment. Background Art

[0002] Existing wafer inspection technologies mainly include optical microscopy, scanning electron microscopy, atomic force microscopy and X-ray inspection technologies. Among them, optical microscopy has a low detection resolution and cannot detect crystal defects such as dislocation and voids; scanning electron microscopy has a slow detection speed and requires contact inspection of the wafer, which may damage the wafer; atomic force microscopy has a slow detection speed and can only detect the wafer surface, and cannot inspect the inside of the wafer, that is, it cannot detect crystal defects in the wafer; X-ray inspection technology has a low detection resolution and it is difficult to detect tiny defects in the wafer. Therefore, existing wafer inspection technologies cannot achieve non-destructive, fast and accurate detection of crystal defects in wafers.

[0003] Therefore, the existing technology needs to be improved and developed. Summary of the invention

[0004] The purpose of this application is to provide a wafer inspection method and related equipment based on Brillouin spectroscopy, aiming to solve the problem that existing wafer inspection technology cannot achieve non-destructive, rapid and accurate detection of crystal defects in wafers.

[0005] In a first aspect, the present application provides a wafer detection method based on Brillouin spectroscopy, which is applied to a spectrum detection system, wherein the spectrum detection system includes a laser source, a light splitting element, a focusing element, and a motion mechanism arranged in sequence according to an optical path, wherein the motion mechanism is used to carry and drive the wafer displacement to switch the detection position point; The spectral detection system also includes: A spectrum detection device is arranged on one side of the light splitter and is used to receive Brillouin scattered light excited by the laser at a detection position of the wafer to detect Brillouin spectrum information; The detection method is performed in the process of the motion mechanism driving the wafer to move, and the detection method includes the following steps: S1. Obtaining the measured half-width and measured frequency shift according to the Brillouin spectrum information; S2. Calculate the regularity of the lattice arrangement based on the measured half-width, measured frequency shift, standard half-width and standard frequency shift. The regularity of the lattice arrangement is used to characterize whether there are crystal defects at the corresponding detection position point of the wafer.

[0006] The Brillouin spectroscopy-based wafer inspection method of the present application calculates the lattice arrangement regularity according to the measured half-width, measured frequency shift, standard half-width and standard frequency shift. Brillouin spectroscopy detection can be achieved by only stimulating the wafer to emit Brillouin scattered light, and the crystal defects of the wafer can be non-destructively detected. In addition, the present application drives the wafer displacement based on a motion mechanism, and can quickly perform Brillouin spectroscopy detection on the wafer, so that the lattice arrangement regularity of each inspection position point of the wafer can be quickly calculated for crystal defect detection. In addition, the present application detects defects based on the lattice arrangement regularity, and can accurately detect crystal defects of the wafer.

[0007] Furthermore, the process of calculating the regularity of the lattice arrangement according to the measured half-height width, the measured frequency shift, the standard half-height width and the standard frequency shift is based on the following formula: ; Wherein, D is the regularity of the lattice arrangement, Γ is the measured half-width, Γ0 is the standard half-width, Δf is the measured frequency shift, Δf0 is the standard frequency shift, and a and b are the first weight and the second weight, respectively.

[0008] In this embodiment, the present application can obtain the lattice arrangement regularity to perform crystal defect detection on the wafer, and the lattice arrangement regularity of the detection position point of the present application can accurately characterize the level of crystal defects at the detection position point.

[0009] Further, the spectrum detection system is used to detect Brillouin spectrum information about the detection position point at different temperatures; The detection method also includes the following steps: S3. When a plurality of Brillouin spectrum information at different temperatures about the detection position points is detected, a plurality of measured frequency shifts at different temperatures about the detection position points are obtained based on all Brillouin spectrum information, and the thermal expansion coefficient is calculated based on all measured frequency shifts about the detection position points; In this embodiment, the present application can obtain the measured frequency shift at different temperatures based on multiple Brillouin spectrum information about the detection position points at different temperatures, and calculate the thermal expansion coefficient based on the measured frequency shifts at multiple different temperatures. It can non-destructively, quickly and accurately detect the thermal expansion coefficient at the detection position point of the wafer, thereby facilitating the analysis of the thermal properties of the wafer.

[0010] Further, the process of calculating the thermal expansion coefficient based on all measured frequency shifts about the detection position point includes: S31. Calculate the phonon velocity at the detection position points at multiple different temperatures based on the measured frequency shift at multiple different temperatures about the detection position points based on the following formula: ; Where v is the phonon velocity, λ is the wavelength of the laser emitted by the laser source, Δf is the measured frequency shift, and n is the refractive index of the wafer; S32. A curve of the phonon velocity at the detection position point with respect to temperature is obtained by fitting all phonon velocities at the detection position point to obtain a functional expression of the phonon velocity at the detection position point with respect to temperature; S33. Calculate the function of the elastic coefficient at the detection position point with respect to the temperature based on the following formula according to the function of the phonon velocity at the detection position point with respect to the temperature: ; Where T is temperature, M(T) is the elastic coefficient as a function of temperature, ρ is the density of the wafer, and v(T) is the phonon velocity as a function of temperature; S34. Calculate the thermal expansion coefficient based on the following formula according to the elastic coefficient at the detection position point as a function of temperature: ; Wherein, α is the thermal expansion coefficient, and dM / dT is the derivative of the thermal expansion coefficient with respect to temperature.

[0011] Furthermore, after step S1, the following steps are also included: S4. When the measured half-width and the measured frequency shift are obtained, the viscosity coefficient and the elastic coefficient are calculated according to the measured half-width and the measured frequency shift.

[0012] Furthermore, the process of calculating the viscosity coefficient and the elastic coefficient according to the measured half-height width and the measured frequency shift is based on the following formula: ; ; ; Wherein, v is the phonon velocity, λ is the wavelength of the laser emitted by the laser source, Δf is the measured frequency shift, n is the refractive index of the wafer, η is the viscosity coefficient, ρ is the density of the wafer, Γ is the measured half-height width, and M is the elastic coefficient.

[0013] Furthermore, after step S1, the following steps are also included: S5. When the measured half-width and the measured frequency shift are obtained, the thermal conductivity is calculated according to the measured half-width and the measured frequency shift.

[0014] In a second aspect, the present application provides a spectrum detection system, including a laser source, a beam splitter, a focusing element, and a motion mechanism arranged in sequence according to an optical path, wherein the motion mechanism is used to carry and drive a wafer displacement to switch a detection position point; The spectral detection system also includes: A spectrum detection device is arranged on one side of the light splitter and is used to receive Brillouin scattered light excited by the laser at a detection position of the wafer to detect Brillouin spectrum information; A controller, used for obtaining the measured half-width and the measured frequency shift according to the Brillouin spectrum information in the process of the motion mechanism driving the wafer displacement; The controller is also used to calculate the lattice arrangement regularity based on the measured half-width, measured frequency shift, standard half-width and standard frequency shift. The lattice arrangement regularity is used to characterize whether there are crystal defects at the corresponding detection position point of the wafer.

[0015] The spectral detection system provided in the present application calculates the lattice arrangement regularity based on the measured half-width, measured frequency shift, standard half-width and standard frequency shift. Brillouin spectral detection can be achieved by only stimulating the wafer to emit Brillouin scattered light, and can non-destructively detect crystal defects of the wafer. In addition, the present application drives the wafer displacement based on a motion mechanism, and can quickly perform Brillouin spectral detection on the wafer, so that the lattice arrangement regularity of each detection position point of the wafer can be quickly calculated for crystal defect detection. In addition, the present application detects defects based on the lattice arrangement regularity, and can accurately detect crystal defects of the wafer.

[0016] In a third aspect, the present application provides an electronic device, including a processor and a memory, wherein the memory stores a computer program executable by the processor, and when the processor executes the computer program, it runs the steps in any of the above methods.

[0017] In a fourth aspect, the present application provides a storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps in any of the above methods are performed.

[0018] From the above, it can be seen that the present application provides a wafer detection method based on Brillouin spectroscopy and related equipment, wherein the wafer detection method based on Brillouin spectroscopy provided by the present application calculates the lattice arrangement regularity according to the measured half-width, measured frequency shift, standard half-width and standard frequency shift, and Brillouin spectroscopy detection can be realized only by exciting the wafer to emit Brillouin scattered light, and the crystal defects of the wafer can be detected non-destructively. In addition, the present application drives the wafer displacement based on a motion mechanism, and can quickly perform Brillouin spectroscopy detection on the wafer, so that the lattice arrangement regularity of each detection position point of the wafer can be quickly calculated for crystal defect detection, and the present application detects defects based on the lattice arrangement regularity, and can accurately detect crystal defects of the wafer.

[0019] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the embodiments of the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A flow chart of a wafer detection method based on Brillouin spectroscopy provided in an embodiment of the present application.

[0021] Figure 2 A schematic diagram of the structure of a spectral detection system provided in an embodiment of the present application.

[0022] Figure 3 A schematic diagram of the optical path of the spectral detection system provided in an embodiment of the present application.

[0023] Figure 4 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0024] Explanation of reference numerals: 1. Laser source; 2. Spectral splitter; 3. Focusing element; 4. Moving mechanism; 5. Spectral detection device; 6. Half-wave plate; 7. Polarizer; 8. Analyzer; 9. Converging mirror; 10. Pinhole filter; 301. Processor; 302. Memory; 303. Communication bus. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0026] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0027] First, as Figure 1 , Figure 2 and Figure 3 As shown, the present application provides a wafer detection method based on Brillouin spectroscopy, which is applied to a spectrum detection system. The spectrum detection system includes a laser source 1, a light splitting element 2, a focusing element 3 and a motion mechanism 4 arranged in sequence according to an optical path. The motion mechanism 4 is used to carry and drive the wafer displacement to switch the detection position point; The spectral detection system also includes: The spectrum detection device 5 is arranged on one side of the light splitter 2 and is used to receive the Brillouin scattered light excited by the laser at the detection position of the wafer to detect the Brillouin spectrum information; The detection method is performed during the process of the motion mechanism 4 driving the wafer to move, and the detection method includes the following steps: S1. Obtaining the measured half-width and measured frequency shift according to the Brillouin spectrum information; S2. Calculate the regularity of the lattice arrangement based on the measured half-width, measured frequency shift, standard half-width and standard frequency shift. The regularity of the lattice arrangement is used to characterize whether there are crystal defects at the corresponding detection position point of the wafer.

[0028] Specifically, when the laser source 1 emits laser, the focusing element 3 focuses the laser that passes through the beam splitter 2 so that the focal point of the laser falls on the surface of the wafer or inside the wafer. The focal point of the laser is the detection position point.

[0029] More specifically, the Brillouin spectrum information is the Brillouin spectrum acquired by the spectrum detection device 5 based on the Brillouin scattered light excited at the detection position of the wafer. The motion mechanism 4 can be a mechanism such as a three-dimensional moving workbench that can carry and drive the wafer to move in any direction. The spectrum detection device 5 can be an existing device such as a Brillouin detector that can receive Brillouin scattered light to detect Brillouin spectrum information.

[0030] More specifically, the working process of the spectral detection system is that the laser source 1 emits laser, the laser irradiates the wafer through the spectrometer 2 and the focusing element 3 to stimulate Brillouin scattered light at the detection position of the wafer, and the Brillouin scattered light is received by the spectral detection device 5 through the focusing element 3 and the spectrometer 2. The spectral detection device 5 detects Brillouin spectral information based on the received Brillouin scattered light stimulated at the corresponding detection position of the wafer.

[0031] More specifically, the measured half-width and the measured frequency shift are the half-width and frequency shift of the Brillouin spectrum information corresponding to the current detection position of the wafer to be detected. There is a central elastic scattering spectrum peak in the Brillouin spectrum information, with Stokes peak and anti-Stokes peak on both sides of it, and the average of the half-width of the Stokes peak and the half-width of the anti-Stokes peak is the measured half-width, and the average of the frequency shifts of the Stokes peak and the anti-Stokes peak compared to the central elastic scattering spectrum peak is the measured frequency shift; the standard half-width and the standard frequency shift are the half-width and frequency shift of the Brillouin spectrum information of a wafer that meets the requirements, has the same lattice and is made of the same material as the wafer to be detected, and a wafer that meets the requirements is a wafer without crystal defects.

[0032] More specifically, the size of the measured half-height width is related to the level of crystal defects at the inspection position point of the wafer, and the absolute difference between the absolute value of the measured frequency shift and the absolute value of the standard frequency shift is related to the level of crystal defects at the inspection position point of the wafer, as explained below: When the internal structure of the wafer is assumed to be a diamond cubic structure and analyzed based on a one-dimensional lattice model in which all atoms are arranged in a straight line, the expression for the frequency of phonons in the wafer is: (1) Where k is the wave vector of the sound wave propagating in the crystal lattice of the wafer, ω(k) is the frequency of the phonon, and C i is the force constant, m is the mass of the silicon atom, a c is the lattice constant, where C i The expression is: (2) Where C0 is the average force constant, δ i is the random disturbance caused by the crystal defect at the detection position of the wafer. When there is a crystal defect at the detection position of the wafer, the higher the level of the crystal defect, the higher the |δ i | is larger, when there is no crystal defect at the detection point of the waferδ i is 0, the level of crystal defects is the degree to which the lattice structure of the wafer deviates from the ideal lattice structure; The expression for the phonon velocity is: (3) Where v is the phonon velocity, and the expression for the frequency shift of the Brillouin spectrum of the Brillouin scattered light excited at the detection position point of the wafer is: (4) Where Δf' is the Brillouin spectrum frequency shift of the Brillouin scattered light excited at the detection position of the wafer, n is the refractive index of the wafer, λ is the wavelength of the laser emitted by the laser source 1, and θ is the scattering angle of the Brillouin scattered light corresponding to Δf'. It can be seen from equations (1), (2), (3) and (4) that the frequency shift of the Brillouin spectrum of the Brillouin scattered light excited at the detection position of the wafer can be expressed as a function of the random disturbance caused by the crystal defects at the detection position of the wafer. Therefore, taking Δf as the measured frequency shift, Δf=Δf', and Δf can also be expressed as a function of the random disturbance caused by the crystal defects at the detection position of the wafer; C i ' is the force constant corresponding to the wafer without crystal defects at the detection position, then C i ' is C0. From formula (2), it can be seen that when there is a crystal defect at the detection position of the wafer, the higher the level of the crystal defect, the higher the |δ i The larger the |C i -C i The larger the | is, the larger the phonon frequency is. Taking ω'(k) as the frequency of the phonon corresponding to the wafer without crystal defects at the detection position, it can be seen from formula (1) that |C i -C iThe larger the value of '|, the larger the value of |ω(k)-ω'(k)|; Taking v' as the phonon velocity of the wafer without crystal defects at the detection position, it can be seen from formula (3) that the larger the value of |ω(k)-ω'(k)|, the larger the value of |v-v'|; Taking Δf0 as the standard frequency shift, it can be seen from Δf=Δf' and formula (4) that the larger the value of |v-v'|, the larger the value of ||Δf0|-|Δf||, so the absolute difference between the absolute value of the measured frequency shift corresponding to the detection position and the absolute value of the standard frequency shift is positively correlated with the level of crystal defects at the detection position; In addition, the ratio of the number of defective lattices at the detection position to the number of all lattices at the detection position is defined as the defect ratio p. Since the phonon lifetime is the average time for a phonon to propagate before being scattered, the larger the mean free path of the phonon, that is, the larger the average path length of the phonon propagation before being scattered, the longer the phonon lifetime; and from the existing relevant theories of the mean free path of phonons, it can be seen that the higher the level of crystal defects at the detection position, the larger p is, and the smaller the mean free path of the phonon at the detection position, so the phonon lifetime at the detection position is negatively correlated with the level of crystal defects at the detection position; and from the uncertainty principle, it can be seen that the smaller the phonon lifetime at the detection position, the larger the measured half-width, so the corresponding measured half-width at the detection position is positively correlated with the level of crystal defects at the detection position.

[0033] More specifically, from the above conclusions, it can be seen that the absolute difference between the absolute value of the measured frequency shift corresponding to the detection position point and the absolute value of the standard frequency shift is positively correlated with the level of crystal defects at the detection position point, and the measured half-width corresponding to the detection position point is positively correlated with the level of crystal defects at the detection position point. Therefore, the lattice arrangement regularity calculated based on the measured half-width and the absolute difference between the absolute value of the measured frequency shift and the absolute value of the standard frequency shift can characterize whether there are crystal defects at the detection position point of the detection wafer, and can characterize the level of crystal defects when there are crystal defects at the detection position point of the detection wafer; in addition, there is a dimensional difference between the absolute difference between the measured half-width and the absolute value of the measured frequency shift and the absolute value of the standard frequency shift. Introducing the standard half-width for calculation can eliminate the dimensional difference, so that the lattice arrangement regularity can more accurately characterize the level of crystal defects. Therefore, the present application calculates the lattice arrangement regularity based on the measured half-width, the measured frequency shift, the standard half-width and the standard frequency shift, and can accurately detect crystal defects of the wafer.

[0034] More specifically, the present application only needs to excite the wafer to emit Brillouin scattered light to achieve Brillouin spectrum detection without causing damage to the wafer; and the present application is based on the motion mechanism 4 to drive the wafer displacement, and can quickly perform Brillouin spectrum detection on the wafer, so that the lattice arrangement regularity of each detection position point of the wafer can be quickly calculated for crystal defect detection.

[0035] The wafer detection method based on Brillouin spectroscopy of the present application calculates the lattice arrangement regularity according to the measured half-width, measured frequency shift, standard half-width and standard frequency shift. Brillouin spectroscopy detection can be achieved by only exciting the wafer to emit Brillouin scattered light, and the crystal defects of the wafer can be detected non-destructively. In addition, the present application drives the wafer displacement based on the motion mechanism 4, and can quickly perform Brillouin spectroscopy detection on the wafer, so that the lattice arrangement regularity of each detection position point of the wafer can be quickly calculated for crystal defect detection. In addition, the present application detects defects based on the lattice arrangement regularity, and can accurately detect crystal defects of the wafer.

[0036] In some preferred embodiments, the process of calculating the regularity of the lattice arrangement according to the measured half-height width, the measured frequency shift, the standard half-height width and the standard frequency shift is based on the following formula: (5) Wherein, D is the regularity of the lattice arrangement, Γ is the measured half-width, Γ0 is the standard half-width, Δf is the measured frequency shift, Δf0 is the standard frequency shift, and a and b are the first weight and the second weight, respectively.

[0037] Specifically, since the absolute difference between the absolute value of the measured frequency shift corresponding to the detection position point and the absolute value of the standard frequency shift is positively correlated with the level of crystal defects at the detection position point, and the measured half-width at half maximum corresponding to the detection position point is positively correlated with the level of crystal defects at the detection position point, in this embodiment, the lattice arrangement regularity is positively correlated with the level of crystal defects. Therefore, the present application can obtain the lattice arrangement regularity to perform crystal defect detection on the wafer, and the present application sets the first weight and the second weight, which can eliminate the dimensional difference between the measured frequency shift and the measured half-width, so that the lattice arrangement regularity of the detection position point can accurately characterize the level of crystal defects at the detection position point. In addition, when the measured half-width corresponding to the detection position point is larger, Γ / Γ0 is also larger, that is, the relative width of the spectral line in the Brillouin spectrum information is larger, which shows that the level of crystal defects at the detection position point is higher, and when the absolute difference between the absolute value of the measured frequency shift corresponding to the detection position point and the absolute value of the standard frequency shift is larger, ||Δf0|-|Δf|| / Δf0 is also larger, that is, the relative difference between the measured frequency shift caused by the crystal defects and the standard frequency shift is larger, which shows that the level of crystal defects at the detection position point is higher. Therefore, the lattice arrangement regularity of the present application can accurately characterize the level of crystal defects at the detection position point.

[0038] In this embodiment, the present application can obtain the lattice arrangement regularity to perform crystal defect detection on the wafer, and the lattice arrangement regularity of the detection position point of the present application can accurately characterize the level of crystal defects at the detection position point.

[0039] In some preferred embodiments, the spectral detection system is used to detect Brillouin spectral information about the detection position at different temperatures; The detection method also includes the following steps: S3. When a plurality of Brillouin spectrum information at different temperatures about the detection position is detected, a plurality of measured frequency shifts at different temperatures about the detection position are obtained based on all the Brillouin spectrum information, and the thermal expansion coefficient is calculated based on all the measured frequency shifts about the detection position.

[0040] Specifically, the thermal expansion coefficient of the wafer at the detection position is related to the temperature of the wafer at the detection position, and the phonon velocity at the detection position at any temperature can be calculated from the measured frequency shift corresponding to the detection position at that temperature. Therefore, the present application can obtain multiple measured frequency shifts at different temperatures about the detection position based on multiple Brillouin spectrum information about the detection position at different temperatures, and calculate the phonon velocities at the detection position at multiple different temperatures based on multiple measured frequency shifts at different temperatures about the detection position, so as to fit the change curve of the phonon velocity at the detection position with respect to temperature, and then obtain the function formula of the phonon velocity at the detection position with respect to temperature.

[0041] Furthermore, the elastic coefficient at the detection position point can be calculated from the phonon velocity at the detection position point, so the present application can calculate the elastic coefficient at the detection position point as a function of the velocity based on the phonon velocity at the detection position point as a function of the temperature; and the thermal expansion coefficient at the detection position point can be calculated from the elastic coefficient at the detection position point, so the present application can calculate the thermal expansion coefficient at the detection position point based on the elastic coefficient at the detection position point as a function of the temperature, wherein the thermal expansion coefficient finally calculated is a function expression about temperature.

[0042] From the above conclusions, it can be known that in some embodiments, the present application can calculate the phonon velocities at the detection position points at multiple different temperatures based on the measured frequency shifts at the detection position points at different temperatures, obtain the function of the phonon velocity at the detection position points with respect to temperature, and calculate the function of the elastic coefficient at the detection position points with respect to velocity, and finally calculate the thermal expansion coefficient at the detection position points. In some other embodiments, the present application can also first calculate the thermal expansion coefficient at the detection position points at multiple different temperatures based on the measured frequency shifts at the detection position points at multiple different temperatures, and then fit the change curve of the thermal expansion coefficient at the detection position points with respect to temperature, and then obtain the function of the thermal expansion coefficient at the detection position points with respect to temperature.

[0043] More specifically, the measured frequency shift in the present embodiment is obtained from Brillouin spectrum information, and the Brillouin spectrum information is obtained based on the Brillouin spectrum detection process. Therefore, the thermal expansion coefficient detection of the present application also has the advantages of being non-destructive, fast and accurate, and the thermal expansion coefficient of the wafer can be used to analyze the thermal properties of the wafer. Therefore, in this embodiment, the present application can obtain the measured frequency shift at different temperatures based on multiple Brillouin spectrum information about detection positions at different temperatures, and calculate the thermal expansion coefficient based on the measured frequency shift at the detection positions at multiple different temperatures. It can non-destructively, quickly and accurately detect the thermal expansion coefficient at the detection position of the wafer, which is convenient for analyzing the thermal properties of the wafer.

[0044] In some preferred embodiments, in step S3, the process of calculating the thermal expansion coefficient based on all measured frequency shifts about the detection position point includes: S31. Calculate the phonon velocity at the detection position points at multiple different temperatures based on all measured frequency shifts about the detection position points based on the following formula: (6) S32. A curve of the phonon velocity at the detection position point with respect to temperature is obtained by fitting all phonon velocities at the detection position point to obtain a functional expression of the phonon velocity at the detection position point with respect to temperature; S33. Calculate the function of the elastic coefficient at the detection position point with respect to the temperature based on the following formula according to the function of the phonon velocity at the detection position point with respect to the temperature: (7) Where T is temperature, M(T) is the elastic coefficient as a function of temperature, ρ is the density of the wafer, and v(T) is the phonon velocity as a function of temperature; S34. Calculate the thermal expansion coefficient based on the following formula according to the elastic coefficient at the detection position point as a function of temperature: (8) Wherein, α is the thermal expansion coefficient, and dM / dT is the derivative of the thermal expansion coefficient with respect to temperature.

[0045] Specifically, since the laser irradiation process of the wafer and the collection process of the Brillouin scattered light excited by the wafer in the present application are both performed based on the focusing element 3, the direction in which the Brillouin scattered light excited by the wafer surface is transmitted to the focusing element 3 in the present application is opposite to the direction in which the laser irradiates the wafer through the focusing element 3, and the scattering angle of the Brillouin scattered light is 180°, so equation (4) can be simplified to equation (6).

[0046] In this embodiment, the present application can detect the thermal expansion coefficient at the detection position of the wafer, which is convenient for analyzing the thermal properties of the wafer.

[0047] In some preferred embodiments, step S1 further includes the following steps: S4. When the measured half-width and the measured frequency shift are obtained, the viscosity coefficient and the elastic coefficient are calculated according to the measured half-width and the measured frequency shift.

[0048] Specifically, the phonon velocity at the detection position can be calculated from the measured frequency shift corresponding to the detection position, and the viscosity coefficient at the detection position can be calculated from the measured frequency shift and the measured half-width corresponding to the detection position, and the elastic coefficient at the detection position can be calculated from the phonon velocity at the detection position. Therefore, the present application can calculate the viscosity coefficient and elastic coefficient at the detection position based on the measured half-width and the measured frequency shift corresponding to the detection position.

[0049] More specifically, the measured half-width and measured frequency shift in the present embodiment are obtained from Brillouin spectrum information, and the Brillouin spectrum information is obtained based on the Brillouin spectrum detection process. Therefore, the viscosity coefficient detection and elastic coefficient detection of the present application also have the advantages of being non-destructive, fast and accurate, and the viscosity coefficient and elastic coefficient of the wafer can be used to analyze the mechanical properties of the wafer. Therefore, in this embodiment, the present application can calculate the viscosity coefficient and elastic coefficient based on the measured half-width and measured frequency shift, and can non-destructively, quickly and accurately detect the viscosity coefficient and elastic coefficient at the detection position of the wafer, which is convenient for analyzing the mechanical properties of the wafer.

[0050] In some preferred embodiments, the process of calculating the viscosity coefficient and the elastic coefficient according to the measured half-height width and the measured frequency shift is based on equation (6) and the following equation: (9) (10) Where η is the viscosity coefficient and M is the elastic coefficient.

[0051] In this embodiment, the present application can detect the viscosity coefficient and the elastic coefficient, which is convenient for analyzing the mechanical properties of the wafer.

[0052] In some preferred embodiments, step S1 further includes the following steps: S5. When the measured half-width and the measured frequency shift are obtained, the thermal conductivity is calculated according to the measured half-width and the measured frequency shift.

[0053] Specifically, the phonon velocity at the detection position can be calculated from the measured frequency shift corresponding to the detection position, and the phonon lifetime at the detection position can be calculated from the measured half-width corresponding to the detection position, and the mean free path of the phonons at the detection position can be calculated from the phonon velocity and phonon lifetime at the detection position, and the thermal conductivity at the detection position can be calculated from the mean free path of the phonons at the detection position. Therefore, the present application can calculate the thermal conductivity at the detection position based on the measured half-width and measured frequency shift corresponding to the detection position.

[0054] More specifically, the measured half-width and measured frequency shift in the present embodiment are obtained from Brillouin spectrum information, and the Brillouin spectrum information is obtained based on the Brillouin spectrum detection process. Therefore, the thermal conductivity detection of the present application also has the advantages of being non-destructive, fast and accurate, and the thermal conductivity of the wafer can be used to analyze the thermal properties of the wafer. Therefore, in this embodiment, the present application can calculate the thermal conductivity based on the measured half-width and the measured frequency shift, and can non-destructively, quickly and accurately detect the thermal conductivity at the detection position of the wafer, which is convenient for analyzing the thermal properties of the wafer.

[0055] Preferably, the process of calculating the thermal conductivity based on the measured half-width and the measured frequency shift is based on equation (6) and the following equation: (11) (12) (13) Where τ is the phonon lifetime, l is the mean free path of the phonon, and C v is the volume specific heat capacity of the wafer, and κ is the thermal conductivity.

[0056] In this embodiment, the present application can detect thermal conductivity, which is convenient for analyzing the thermal properties of the wafer.

[0057] Second, as Figure 2 and Figure 3 As shown, the present application provides a spectrum detection system, comprising a laser source 1, a beam splitter 2, a focusing member 3 and a motion mechanism 4 arranged in sequence according to an optical path, wherein the motion mechanism 4 is used to carry and drive the wafer displacement to switch the detection position point; The spectral detection system also includes: The spectrum detection device 5 is arranged on one side of the light splitter 2 and is used to receive the Brillouin scattered light excited by the laser at the detection position of the wafer to detect the Brillouin spectrum information; A controller, used for obtaining the measured half-width and the measured frequency shift according to the Brillouin spectrum information during the process of the motion mechanism 4 driving the wafer displacement; The controller is also used to calculate the lattice arrangement regularity based on the measured half-width, measured frequency shift, standard half-width and standard frequency shift. The lattice arrangement regularity is used to characterize whether there are crystal defects at the corresponding detection position point of the wafer.

[0058] The spectral detection system of the present application calculates the lattice arrangement regularity based on the measured half-width, measured frequency shift, standard half-width and standard frequency shift. Brillouin spectral detection can be achieved by only stimulating the wafer to emit Brillouin scattered light, and can non-destructively detect crystal defects of the wafer. In addition, the present application drives the wafer displacement based on the motion mechanism 4, and can quickly perform Brillouin spectral detection on the wafer, so that the lattice arrangement regularity of each detection position point of the wafer can be quickly calculated for crystal defect detection. In addition, the present application detects defects based on the lattice arrangement regularity, and can accurately detect crystal defects of the wafer.

[0059] Preferably, a half wave plate 6 and a polarizer 7 are sequentially arranged between the laser source 1 and the beam splitter 2 according to the optical path.

[0060] Preferably, a polarizer 8, a converging mirror 9 and a pinhole filter 10 are sequentially arranged between the light splitting element 2 and the spectrum detection device 5 according to the optical path.

[0061] Thirdly, Figure 4 As shown, the present application provides an electronic device, including a processor 301 and a memory 302, the processor 301 and the memory 302 are interconnected and communicate with each other through a communication bus 303 and / or other forms of connection mechanisms (not marked), the memory 302 stores a computer program executable by the processor 301, and when the electronic device is running, the processor 301 executes the computer program to execute the method in any optional implementation of the above embodiment to achieve the following functions: obtaining the measured half-width and the measured frequency shift according to the Brillouin spectrum information; calculating the lattice arrangement regularity according to the measured half-width, the measured frequency shift, the standard half-width and the standard frequency shift, and the lattice arrangement regularity is used to characterize whether there are crystal defects at the corresponding detection position point of the wafer.

[0062] In a fourth aspect, an embodiment of the present application provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the method in any optional implementation of the above embodiment is executed to achieve the following functions: obtaining the measured half-width and the measured frequency shift according to the Brillouin spectrum information; calculating the lattice arrangement regularity according to the measured half-width, the measured frequency shift, the standard half-width and the standard frequency shift, and the lattice arrangement regularity is used to characterize whether there are crystal defects at the corresponding detection position of the wafer. Among them, the computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, referred to as SRAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, referred to as EEPROM), erasable programmable read-only memory (Erasable Programmable Read Only Memory, referred to as EPROM), programmable read-only memory (Programmable Red-Only Memory, referred to as PROM), read-only memory (Read-Only Memory, referred to as ROM), magnetic memory, flash memory, disk or optical disk.

[0063] In summary, the present application provides a wafer inspection method based on Brillouin spectroscopy and related equipment, wherein the wafer inspection method based on Brillouin spectroscopy provided by the present application calculates the lattice arrangement regularity according to the measured half-width, measured frequency shift, standard half-width and standard frequency shift, and Brillouin spectroscopy detection can be achieved only by exciting the wafer to emit Brillouin scattered light, and the crystal defects of the wafer can be non-destructively detected. In addition, the present application drives the wafer displacement based on the motion mechanism 4, and can quickly perform Brillouin spectroscopy detection on the wafer, so that the lattice arrangement regularity of each detection position point of the wafer can be quickly calculated for crystal defect detection, and the present application detects defects based on the lattice arrangement regularity, and can accurately detect crystal defects of the wafer.

[0064] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0065] In addition, the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0066] Furthermore, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0067] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0068] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A wafer detection method based on Brillouin spectroscopy, applied to a spectrum detection system, characterized in that: The spectrum detection system comprises a laser source (1), a light splitting element (2), a focusing element (3) and a motion mechanism (4) which are arranged in sequence according to an optical path, wherein the motion mechanism (4) is used to carry and drive the wafer to move so as to switch the detection position point; The spectrum detection system also includes: A spectrum detection device (5) is arranged on one side of the light splitting element (2) and is used to receive Brillouin scattered light generated based on laser excitation at a detection position of the wafer to detect Brillouin spectrum information; The detection method is performed during the process of the motion mechanism (4) driving the wafer to move, and the detection method comprises the following steps: S1. Obtaining the measured half-width and measured frequency shift according to the Brillouin spectrum information; S2. Calculate the lattice arrangement regularity based on the measured half-width, the measured frequency shift, the standard half-width and the standard frequency shift, and the lattice arrangement regularity is used to characterize whether there are crystal defects at the corresponding detection position point of the wafer.

2. The wafer detection method based on Brillouin spectroscopy according to claim 1, characterized in that: The process of calculating the lattice arrangement regularity according to the measured half-width, the measured frequency shift, the standard half-width and the standard frequency shift is performed based on the following formula: ； Wherein, D is the regularity of the lattice arrangement, Γ is the measured half-width, Γ0 is the standard half-width, Δf is the measured frequency shift, Δf0 is the standard frequency shift, and a and b are the first weight and the second weight, respectively.

3. The wafer detection method based on Brillouin spectroscopy according to claim 1, characterized in that: The spectrum detection system is used to detect Brillouin spectrum information about the detection position point at different temperatures; The detection method further comprises the following steps: S3. When a plurality of Brillouin spectrum information at different temperatures about the detection position is detected, a plurality of measured frequency shifts at different temperatures about the detection position are obtained based on all the Brillouin spectrum information, and the thermal expansion coefficient is calculated based on all the measured frequency shifts about the detection position.

4. The wafer detection method based on Brillouin spectroscopy according to claim 3, characterized in that: In step S3, the process of calculating the thermal expansion coefficient according to all measured frequency shifts about the detection position point includes: S31. Calculate the phonon velocity at the detection position points at multiple different temperatures based on all measured frequency shifts about the detection position points based on the following formula: ； Wherein, v is the phonon velocity, λ is the wavelength of the laser emitted by the laser source (1), Δf is the measured frequency shift, and n is the refractive index of the wafer; S32. A curve of the phonon velocity at the detection position point with respect to temperature is obtained by fitting all phonon velocities at the detection position point to obtain a functional expression of the phonon velocity at the detection position point with respect to temperature; S33. Calculate the function of the elastic coefficient at the detection position point with respect to the temperature based on the following formula according to the function of the phonon velocity at the detection position point with respect to the temperature: ； Where T is temperature, M(T) is the elastic coefficient as a function of temperature, ρ is the density of the wafer, and v(T) is the phonon velocity as a function of temperature; S34. Calculate the thermal expansion coefficient based on the following formula according to the elastic coefficient at the detection position point as a function of temperature: ； Wherein, α is the thermal expansion coefficient, and dM / dT is the derivative of the thermal expansion coefficient with respect to temperature.

5. The wafer detection method based on Brillouin spectroscopy according to claim 1, characterized in that: The step S1 further includes the following steps: S4. When the measured half-width and the measured frequency shift are obtained, the viscosity coefficient and the elastic coefficient are calculated according to the measured half-width and the measured frequency shift.

6. The wafer detection method based on Brillouin spectroscopy according to claim 5, characterized in that: The process of calculating the viscosity coefficient and the elastic coefficient according to the measured half-height width and the measured frequency shift is based on the following formula: ； ； ； Wherein, v is the phonon velocity, λ is the wavelength of the laser emitted by the laser source (1), Δf is the measured frequency shift, n is the refractive index of the wafer, η is the viscosity coefficient, ρ is the density of the wafer, Γ is the measured half-width, and M is the elastic modulus.

7. The wafer detection method based on Brillouin spectroscopy according to claim 1, characterized in that: The step S1 further includes the following steps: S5. When the measured half-width and the measured frequency shift are obtained, thermal conductivity is calculated according to the measured half-width and the measured frequency shift.

8. A spectrum detection system, characterized in that: It comprises a laser source (1), a beam splitter (2), a focusing element (3) and a motion mechanism (4) which are arranged in sequence along an optical path, wherein the motion mechanism (4) is used to carry and drive the wafer to move so as to switch a detection position point; The spectrum detection system also includes: A spectrum detection device (5) is arranged on one side of the light splitting element (2) and is used to receive Brillouin scattered light generated based on laser excitation at a detection position of the wafer to detect Brillouin spectrum information; A controller, used for obtaining the measured half-width and the measured frequency shift according to the Brillouin spectrum information during the process of the motion mechanism (4) driving the wafer to move; The controller is also used to calculate the lattice arrangement regularity based on the measured half-width, the measured frequency shift, the standard half-width and the standard frequency shift, and the lattice arrangement regularity is used to characterize whether there are crystal defects at the corresponding detection position point of the wafer.

9. An electronic device, characterized in that: The invention comprises a processor (301) and a memory (302), wherein the memory (302) stores a computer program executable by the processor (301), and when the processor (301) executes the computer program, the steps in any one of the methods according to claims 1 to 7 are performed.

10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor (301), the steps of the method according to any one of claims 1 to 7 are performed.

Images