Wafer detection method and related equipment based on Brillouin spectroscopy

Abstract

The present invention discloses a wafer detection method based on Brillouin spectroscopy and related equipment, and relates to the field of wafer detection technology, wherein the wafer detection method based on Brillouin spectroscopy includes the following steps: obtaining the measured half-width and the measured frequency shift according to the Brillouin spectroscopy 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. The wafer detection method based on Brillouin spectroscopy of the present application can solve the problem that the existing wafer detection technology cannot realize non-destructive, rapid and accurate detection of crystal defects of wafers, and can non-destructively, rapidly and accurately detect crystal defects of wafers.

Description

Technical Field

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

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

[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 detection method and related equipment based on Brillouin spectroscopy, aiming to solve the problem that the existing wafer detection technologies cannot achieve non-destructive, fast, and accurate detection of the crystal defects of the wafer.

[0005] In the first aspect, this application provides a wafer detection method based on Brillouin spectroscopy, which is applied to a spectral detection system. The spectral detection system includes a laser source, a beam splitter, a focusing element, and a motion mechanism arranged in sequence according to the optical path. The motion mechanism is used to carry and drive the wafer to displace to switch the detection position points;

[0006] The spectral detection system further includes:

[0007] A spectral detection device, arranged on one side of the beam splitter, for receiving the Brillouin scattered light excited by the laser at the detection position points of the wafer to detect Brillouin spectral information;

[0008] The detection method is executed during the process of the motion mechanism driving the wafer to displace, and the detection method includes the following steps:

[0009] S1. Obtain the measured full width at half maximum and the measured frequency shift according to the Brillouin spectral information;

[0010] S2. Calculate the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift. The lattice arrangement regularity is used to characterize whether there are crystal defects at the corresponding detection position points of the wafer.

[0011] The wafer detection method based on Brillouin spectroscopy of the present application calculates the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift. It only needs to excite Brillouin scattered light on the wafer to achieve Brillouin spectroscopy detection, can nondestructively detect the crystal defects of the wafer, and the present application drives the wafer displacement based on a motion mechanism, can quickly perform Brillouin spectroscopy detection on the wafer, so as to quickly calculate the lattice arrangement regularity of each detection position point of the wafer for crystal defect detection, and the present application detects defects based on the lattice arrangement regularity, can accurately detect the crystal defects of the wafer.

[0012] Further, the process of calculating the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift is carried out based on the following formula:

[0013] ;

[0014] where D is the lattice arrangement regularity, Γ is the measured full width at half maximum, Γ 0 is the standard full width at half maximum, Δf is the measured frequency shift, Δf 0 is the standard frequency shift, and a and b are the first weight and the second weight respectively.

[0015] In this embodiment, the present application can obtain the lattice arrangement regularity to detect the crystal defects of the wafer, and the lattice arrangement regularity of the detection position points of the present application can accurately characterize the level of crystal defects at the detection position points.

[0016] Further, the spectroscopic detection system is used to detect Brillouin spectroscopic information about the detection position points at different temperatures;

[0017] The detection method further includes the following steps:

[0018] S3. When detecting multiple Brillouin spectroscopic information about the detection position points at different temperatures, based on all the Brillouin spectroscopic information, obtain multiple measured frequency shifts about the detection position points at different temperatures, and calculate the thermal expansion coefficient according to all the measured frequency shifts about the detection position points;

[0019] In this embodiment, the present application can obtain the measured frequency shifts at different temperatures based on multiple Brillouin spectroscopic 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, can nondestructively, quickly and accurately detect the thermal expansion coefficient at the detection position points of the wafer, which is convenient for analyzing the thermal properties of the wafer.

[0020] Further, the process of calculating the thermal expansion coefficient according to all the measured frequency shifts about the detection position points includes:

[0021] S31. Calculate the phonon velocities at the detection position points at multiple different temperatures based on the following formula according to the measured frequency shifts at the detection position points at multiple different temperatures:

[0022] ;

[0023] 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;

[0024] S32. Fit the phonon velocities at the detection position points to obtain the curve of the phonon velocity at the detection position point with respect to temperature, so as to obtain the functional formula of the phonon velocity at the detection position point with respect to temperature;

[0025] S33. Calculate the functional formula of the elastic coefficient at the detection position point with respect to temperature based on the following formula according to the functional formula of the phonon velocity at the detection position point with respect to temperature:

[0026] ;

[0027] where T is the temperature, M(T) is the functional formula of the elastic coefficient with respect to temperature, ρ is the density of the wafer, and v(T) is the functional formula of the phonon velocity with respect to temperature;

[0028] S34. Calculate the thermal expansion coefficient based on the following formula according to the functional formula of the elastic coefficient at the detection position point with respect to temperature: ;

[0029] where α is the thermal expansion coefficient, and dM / dT is the derivative of the thermal expansion coefficient with respect to temperature.

[0030] Furthermore, after step S1, the following steps are also included:

[0031] S4. When the measured full width at half maximum and the measured frequency shift are obtained, calculate the viscosity coefficient and the elastic coefficient according to the measured full width at half maximum and the measured frequency shift.

[0032] Furthermore, the process of calculating the viscosity coefficient and the elastic coefficient according to the measured full width at half maximum and the measured frequency shift is carried out based on the following formula:

[0033] ;

[0034] ;

[0035] ;

[0036] where 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 full width at half maximum, and M is the elastic coefficient.

[0037] Further, after step S1, the following steps are further included:

[0038] S5. When the measured full width at half maximum and the measured frequency shift are obtained, calculate the thermal conductivity according to the measured full width at half maximum and the measured frequency shift.

[0039] In a second aspect, the present application provides a spectral detection system, including a laser source, a beam splitter, a focusing member, and a motion mechanism arranged in sequence along the optical path. The motion mechanism is used to carry and drive the wafer to displace to switch the detection position points;

[0040] The spectral detection system further includes:

[0041] A spectral detection device, arranged on one side of the beam splitter, for receiving the Brillouin scattered light excited by the laser at the detection position points of the wafer to detect Brillouin spectral information;

[0042] A controller, configured to obtain the measured full width at half maximum and the measured frequency shift according to the Brillouin spectral information during the process of the motion mechanism driving the wafer to displace;

[0043] The controller is further configured to calculate the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift. The lattice arrangement regularity is used to characterize whether there are crystal defects at the corresponding detection position points of the wafer.

[0044] The spectral detection system provided by the present application calculates the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift. Only by making the wafer excite Brillouin scattered light can Brillouin spectral detection be realized. It can nondestructively detect the crystal defects of the wafer. And based on the motion mechanism driving the wafer to displace, the present application can quickly perform Brillouin spectral detection on the wafer, so as to quickly calculate the lattice arrangement regularity of each detection position point of the wafer for crystal defect detection. And based on the lattice arrangement regularity to detect defects, the present application can accurately detect the crystal defects of the wafer.

[0045] In a third aspect, the present application provides an electronic device, including a processor and a memory. The memory stores a computer program executable by the processor. When the processor executes the computer program, it runs the steps in any of the above methods.

[0046] In a fourth aspect, the present application provides a storage medium, on which a computer program is stored. When the computer program is executed by a processor, it runs the steps in any of the above methods.

[0047] As described above, the present application provides a wafer detection method and related equipment based on Brillouin spectroscopy. The wafer detection method based on Brillouin spectroscopy provided by the present application calculates the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift. Only by exciting Brillouin scattered light on the wafer can Brillouin spectroscopy detection be realized, and crystal defects of the wafer can be detected nondestructively. Moreover, the present application drives the wafer to displace 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 the crystal defects of the wafer.

[0048] Other features and advantages of the present application will be described in the subsequent specification, and, in part, will be obvious from the specification, or can be understood by implementing the embodiments of the present application. The objectives and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a flowchart of the wafer detection method based on Brillouin spectroscopy provided by an embodiment of the present application.

[0050] Figure 2 It is a schematic structural diagram of the spectral detection system provided by an embodiment of the present application.

[0051] Figure 3 It is a schematic optical path diagram of the spectral detection system provided by an embodiment of the present application.

[0052] Figure 4 It is a schematic structural diagram of the electronic device provided by an embodiment of the present application.

[0053] Reference numerals: 1, laser source; 2, beam splitter; 3, focusing element; 4, motion mechanism; 5, spectral detection device; 6, half-wave plate; 7, polarizer; 8, analyzer; 9, converging lens; 10, pinhole filter; 301, processor; 302, memory; 303, communication bus. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] Next, in combination with the accompanying drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and illustrated in the accompanying 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 accompanying drawings is not intended to limit the scope of the present application to be protected, but only represents the selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts belong to the scope of protection of the present application.

[0055] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0056] In the first aspect, as Figure 1 、 Figure 2 and Figure 3 shown, the present application provides a wafer detection method based on Brillouin spectroscopy, which is applied to a spectroscopic detection system. The spectroscopic detection system includes a laser source 1, a beam splitter 2, a focusing element 3, and a motion mechanism 4 arranged in sequence according to the optical path. The motion mechanism 4 is used to carry and drive the wafer to displace to switch the detection position points;

[0057] The spectroscopic detection system further includes:

[0058] A spectroscopic detection device 5, arranged on one side of the beam splitter 2, is used to receive the Brillouin scattered light excited by the laser at the detection position points of the wafer to detect Brillouin spectral information;

[0059] The detection method is executed during the process of the motion mechanism 4 driving the wafer to displace, and the detection method includes the following steps:

[0060] S1. Obtain the measured full width at half maximum and the measured frequency shift according to the Brillouin spectral information;

[0061] S2. Calculate the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift. The lattice arrangement regularity is used to characterize whether there are crystal defects at the corresponding detection position points of the wafer.

[0062] Specifically, when the laser source 1 emits laser light, the focusing element 3 focuses the laser light passing through the beam splitter 2 so that the focal point of the laser light falls on the surface or inside of the wafer. The focal point of the laser light is the detection position point.

[0063] More specifically, the Brillouin spectral information is the Brillouin spectrum obtained by the spectral detection device 5 through detecting the Brillouin scattered light excited at the detection position point of the wafer. The motion mechanism 4 can be a three-dimensional moving workbench or other mechanisms that can carry and drive the wafer to displace in any direction. The spectral detection device 5 can be an existing device such as a Brillouin detector that can receive the Brillouin scattered light to detect the Brillouin spectral information.

[0064] More specifically, the working process of the spectral detection system is that the laser source 1 emits laser light, and the laser light irradiates the wafer through the beam splitter 2 and the focusing element 3 to excite Brillouin scattered light at the detection position point of the wafer. The Brillouin scattered light is received by the spectral detection device 5 through the focusing element 3 and the beam splitter 2, and the spectral detection device 5 detects the Brillouin spectral information based on the received Brillouin scattered light excited at the corresponding detection position point of the wafer.

[0065] More specifically, the measured full width at half maximum and the measured frequency shift are the full width at half maximum and the frequency shift of the Brillouin spectral information corresponding to the current detection position point of the wafer to be detected. There is a central elastic scattering spectral peak in the Brillouin spectral information, and a Stokes peak and an anti-Stokes peak exist on both sides respectively. The average value of the full width at half maximum of the Stokes peak and the full width at half maximum of the anti-Stokes peak is the measured full width at half maximum, and the average value of the frequency shifts of the Stokes peak and the anti-Stokes peak relative to the central elastic scattering spectral peak is the measured frequency shift; the standard full width at half maximum and the standard frequency shift are respectively the full width at half maximum and the frequency shift of the Brillouin spectral information of a wafer that meets the requirements, has the same lattice and the same material as the wafer to be detected. The wafer that meets the requirements is a wafer without crystal defects.

[0066] More specifically, the size of the measured full width at half maximum is related to the level of crystal defects at the detection 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 detection position point of the wafer. The explanation is as follows:

[0067] In the case where 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:

[0068] (1)

[0069] where k is the wave vector of the acoustic wave propagating in the lattice of the wafer, ω(k) is the frequency of the phonon, C i is the force constant, m is the mass of the silicon atom, a c is the lattice constant, where the expression of C i is:

[0070] (2)

[0071] where, C 0is the average force constant, δ i is the random perturbation caused by crystal defects at the detection position point of the wafer. When there are crystal defects at the detection position point of the wafer, the higher the level of the crystal defects, the larger |δ i | is. When there are no crystal defects at the detection position point of the wafer, δ i is 0, and the level of the crystal defects is the degree of deviation of the crystal lattice structure of the wafer from the ideal crystal lattice structure;

[0072] The expression for the phonon velocity is:

[0073] (3)

[0074] 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:

[0075] (4)

[0076] where Δf’ is the frequency shift of the Brillouin spectrum of the Brillouin scattered light excited at the detection position point of the wafer, n is the refractive index of the wafer, λ is the wavelength of the laser emitted by 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 point of the wafer can be expressed as a functional formula of the random perturbation caused by crystal defects at the detection position point of the wafer. Therefore, taking Δf as the measured frequency shift, then Δf = Δf’, and Δf can also be expressed as a functional formula of the random perturbation caused by crystal defects at the detection position point of the wafer;

[0077] Taking C i ’ as the force constant corresponding to the wafer without crystal defects at the detection position point, then C i ’ is C 0 . It can be seen from equation (2) that when there are crystal defects at the detection position point of the wafer, the higher the level of the crystal defects, the larger |δ i | is, and the larger |C i - C i ’| is; taking ω’(k) as the frequency of the phonon corresponding to the wafer without crystal defects at the detection position point, it can be seen from equation (1) that when |C i - C i ’| is larger, |ω(k) - ω’(k)| is larger; taking v’ as the phonon velocity corresponding to the wafer without crystal defects at the detection position point, it can be seen from equation (3) that when |ω(k) - ω’(k)| is larger, |v - v’| is larger; taking Δf 0 as the standard frequency shift, it can be seen from Δf = Δf’ and equation (4) that when |v - v’| is larger, ||Δf 0The larger |Δf| is, the more positive 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 related to the level of crystal defects at the detection position point;

[0078] Moreover, define the ratio of the number of defective lattices at the detection position point to the number of all lattices at the detection position point as the defect ratio p. Since the phonon lifetime is the average time for phonons to propagate before being scattered, the larger the average free path of phonons, that is, the larger the average path length for phonons to propagate before being scattered, the larger the phonon lifetime. And according to the existing theory of the average free path of phonons, the higher the level of crystal defects at the detection position point, the larger p is, and the smaller the average free path of phonons at the detection position point is. Therefore, the phonon lifetime at the detection position point is negatively correlated with the level of crystal defects at the detection position point. And according to the uncertainty principle, the smaller the phonon lifetime at the detection position point, the larger the measured full width at half maximum. Therefore, the measured full width at half maximum corresponding to the detection position point is positively correlated with the level of crystal defects at the detection position point.

[0079] More specifically, from the above conclusions, 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 full width at half maximum 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 full width at half maximum, the absolute value of the measured frequency shift, 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 detected wafer, and can characterize the level of crystal defects when there are crystal defects at the detection position point of the detected wafer. In addition, there is a dimensional difference between the measured full width at half maximum and the absolute difference between the absolute value of the measured frequency shift and the absolute value of the standard frequency shift. Introducing the standard full width at half maximum for calculation can eliminate this dimensional difference, enabling the lattice arrangement regularity to more accurately characterize the level of crystal defects. Therefore, the present application calculates the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift, and can accurately detect the crystal defects of the wafer.

[0080] More specifically, the present application only needs to excite Brillouin scattered light from the wafer to achieve Brillouin spectroscopy detection, without causing damage to the wafer. And based on the motion mechanism 4 to drive the wafer displacement, the present application can quickly perform Brillouin spectroscopy detection on the wafer, so as to quickly calculate the lattice arrangement regularity of each detection position point of the wafer for crystal defect detection.

[0081] The wafer detection method based on Brillouin spectroscopy of the present application calculates the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift. Only by exciting Brillouin scattered light on the wafer can Brillouin spectroscopy detection be realized, and the crystal defects of the wafer can be detected nondestructively. Moreover, the present application drives the wafer to displace 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 the crystal defects of the wafer.

[0082] In some preferred embodiments, the process of calculating the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift is carried out based on the following formula:

[0083] (5)

[0084] where D is the lattice arrangement regularity, Γ is the measured full width at half maximum, Γ 0 is the standard full width at half maximum, Δf is the measured frequency shift, Δf 0 is the standard frequency shift, and a and b are the first weight and the second weight respectively.

[0085] 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 full 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 detect the crystal defects of 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 full width at half maximum, so that the lattice arrangement regularity of the detection position point can accurately represent the level of crystal defects at the detection position point. In addition, when the measured full width at half maximum corresponding to the detection position point is larger, Γ / Γ 0 is also larger, that is, the relative width of the spectral line in the Brillouin spectral information is larger, indicating 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, ||Δf 0 |-|Δf|| / Δf 0 is also larger, that is, the relative difference between the measured frequency shift and the standard frequency shift caused by crystal defects is larger, indicating that the level of crystal defects at the detection position point is higher. Therefore, the lattice arrangement regularity of the present application can accurately represent the level of crystal defects at the detection position point.

[0086] In this embodiment, the present application can obtain the lattice arrangement regularity to detect the crystal defects of the wafer, and the lattice arrangement regularity of the detection position point of the present application can accurately represent the level of crystal defects at the detection position point.

[0087] In some preferred embodiments, the spectral detection system is used to detect Brillouin spectral information about the detection position point at different temperatures;

[0088] The detection method further includes the following steps:

[0089] S3. When detecting Brillouin spectral information about the detection position point at multiple different temperatures, obtaining multiple measured frequency shifts about the detection position point at different temperatures based on all the Brillouin spectral information, and calculating the thermal expansion coefficient according to all the measured frequency shifts about the detection position point.

[0090] Specifically, the thermal expansion coefficient of the wafer at the detection position point is related to the temperature at the detection position point of the wafer, and the phonon velocity at the detection position point at any temperature can be calculated from the measured frequency shift corresponding to the detection position point at that temperature. Therefore, the present application can obtain multiple measured frequency shifts about the detection position point at different temperatures based on multiple Brillouin spectral information about the detection position point at different temperatures, and calculate the phonon velocities at the detection position point at multiple different temperatures based on multiple measured frequency shifts about the detection position point at different temperatures, so as to be able to fit and obtain the change curve of the phonon velocity at the detection position point with respect to temperature, and further obtain the functional formula of the phonon velocity at the detection position point with respect to temperature.

[0091] Furthermore, the elastic coefficient at the detection position point can be calculated from the phonon velocity at the detection position point. Therefore, the present application can calculate the functional formula of the elastic coefficient at the detection position point with respect to velocity based on the functional formula of the phonon velocity at the detection position point with respect to temperature; and the thermal expansion coefficient at the detection position point can be calculated from the elastic coefficient at the detection position point. Therefore, the present application can calculate the thermal expansion coefficient at the detection position point based on the functional formula of the elastic coefficient at the detection position point with respect to temperature, where the finally calculated thermal expansion coefficient is a functional expression about temperature.

[0092] From the above conclusions, it can be seen that in some embodiments, the present application can calculate and obtain the phonon velocities at the detection position point at multiple different temperatures based on multiple measured frequency shifts about the detection position point at different temperatures, obtain the functional formula of the phonon velocity at the detection position point with respect to temperature, and calculate the functional formula of the elastic coefficient at the detection position point with respect to velocity, and finally calculate the thermal expansion coefficient at the detection position point. In some other embodiments, the present application can also first calculate and obtain the thermal expansion coefficients at the detection position point at multiple different temperatures based on multiple measured frequency shifts at the detection position point at multiple different temperatures, then fit and obtain the change curve of the thermal expansion coefficient at the detection position point with respect to temperature, and further obtain the functional formula of the thermal expansion coefficient at the detection position point with respect to temperature.

[0093] More specifically, the measured frequency shift in this embodiment is obtained from Brillouin spectral information, and the Brillouin spectral information is obtained based on the Brillouin spectral detection process. Therefore, the detection of the coefficient of thermal expansion in this application also has the advantages of being non-destructive, fast, and accurate. The coefficient of thermal expansion of the wafer can be used to analyze the thermal properties of the wafer. Therefore, in this embodiment, this application can obtain the measured frequency shift at different temperatures based on multiple Brillouin spectral information of the detection position points at different temperatures, and calculate the coefficient of thermal expansion according to the measured frequency shift at the detection position points at multiple different temperatures, and can detect the coefficient of thermal expansion at the detection position points of the wafer non-destructively, quickly, and accurately, which is convenient for analyzing the thermal properties of the wafer.

[0094] In some preferred embodiments, in step S3, the process of calculating the coefficient of thermal expansion according to all the measured frequency shifts regarding the detection position points includes:

[0095] S31. Based on the following formula, calculate the phonon velocities at the detection position points at multiple different temperatures according to all the measured frequency shifts regarding the detection position points:

[0096] (6)

[0097] S32. Fit the phonon velocities at the detection position points to obtain a curve of the phonon velocity at the detection position points with respect to temperature, so as to obtain a functional formula of the phonon velocity at the detection position points with respect to temperature;

[0098] S33. Based on the following formula, calculate a functional formula of the elastic coefficient at the detection position points with respect to temperature according to the functional formula of the phonon velocity at the detection position points with respect to temperature:

[0099] (7)

[0100] where, T is the temperature, M(T) is the functional formula of the elastic coefficient with respect to temperature, ρ is the density of the wafer, and v(T) is the functional formula of the phonon velocity with respect to temperature;

[0101] S34. Based on the following formula, calculate the coefficient of thermal expansion according to the functional formula of the elastic coefficient at the detection position points with respect to temperature:

[0102] (8)

[0103] where, α is the coefficient of thermal expansion, and dM / dT is the derivative of the coefficient of thermal expansion with respect to temperature.

[0104] Specifically, since both the laser irradiation process of the wafer in this application and the collection process of the Brillouin scattered light excited by the wafer are based on the focusing member 3, the direction in which the Brillouin scattered light excited on the wafer surface is transmitted to the focusing member 3 is opposite to the direction in which the laser irradiates the wafer through the focusing member 3, and the scattering angle of the Brillouin scattered light is 180°. Therefore, Equation (4) can be simplified to Equation (6).

[0105] In this embodiment, this application can achieve the detection of the coefficient of thermal expansion at the detection position point of the wafer, which is convenient for analyzing the thermal properties of the wafer.

[0106] In some preferred embodiments, after step S1, the following steps are further included:

[0107] S4. When the measured full width at half maximum and the measured frequency shift are obtained, calculate the viscosity coefficient and the elastic coefficient according to the measured full width at half maximum and the measured frequency shift.

[0108] Specifically, the phonon velocity at the detection position point can be calculated from the measured frequency shift corresponding to the detection position point, the viscosity coefficient at the detection position point can be calculated from the measured frequency shift and the measured full width at half maximum corresponding to the detection position point, and the elastic coefficient at the detection position point can be calculated from the phonon velocity at the detection position point. Therefore, this application can calculate the viscosity coefficient and the elastic coefficient at the detection position point according to the measured full width at half maximum and the measured frequency shift corresponding to the detection position point.

[0109] More specifically, the measured full width at half maximum and the measured frequency shift in this embodiment are obtained from the Brillouin spectral information, and the Brillouin spectral information is obtained based on the Brillouin spectral detection process. Therefore, the detection of the viscosity coefficient and the elastic coefficient in this application also has the advantages of being non-destructive, fast, and accurate. The viscosity coefficient and the elastic coefficient of the wafer can be used to analyze the mechanical properties of the wafer. Therefore, in this embodiment, this application can calculate the viscosity coefficient and the elastic coefficient according to the measured full width at half maximum and the measured frequency shift, and can non-destructively, quickly, and accurately detect the viscosity coefficient and the elastic coefficient at the detection position point of the wafer, which is convenient for analyzing the mechanical properties of the wafer.

[0110] In some preferred embodiments, the process of calculating the viscosity coefficient and the elastic coefficient according to the measured full width at half maximum and the measured frequency shift is based on Equation (6) and the following equation:

[0111] (9)

[0112] (10)

[0113] Where η is the viscosity coefficient and M is the elastic coefficient.

[0114] In this embodiment, this application can achieve the detection of the viscosity coefficient and the elastic coefficient, which is convenient for analyzing the mechanical properties of the wafer.

[0115] In some preferred embodiments, after step S1, the following steps are further included:

[0116] S5. When the measured full width at half maximum and the measured frequency shift are obtained, calculate the thermal conductivity according to the measured full width at half maximum and the measured frequency shift.

[0117] Specifically, the phonon velocity at the detection position point can be calculated from the measured frequency shift corresponding to the detection position point, the phonon lifetime at the detection position point can be calculated from the measured full width at half maximum corresponding to the detection position point, the mean free path of phonons at the detection position point can be calculated from the phonon velocity and the phonon lifetime at the detection position point, and the thermal conductivity at the detection position point can be calculated from the mean free path of phonons at the detection position point. Therefore, in this application, the thermal conductivity at the detection position point can be calculated according to the measured full width at half maximum and the measured frequency shift corresponding to the detection position point.

[0118] More specifically, the measured full width at half maximum and the measured frequency shift in this embodiment are obtained from the Brillouin spectral information, and the Brillouin spectral information is obtained based on the Brillouin spectral detection process. Therefore, the thermal conductivity detection of this application also has the advantages of being non-destructive, fast, and accurate. The thermal conductivity of the wafer can be used to analyze the thermal properties of the wafer. Therefore, in this embodiment, this application can calculate the thermal conductivity according to the measured full width at half maximum and the measured frequency shift, can detect the thermal conductivity at the detection position point of the wafer non-destructively, quickly, and accurately, and is convenient for analyzing the thermal properties of the wafer.

[0119] Preferably, the process of calculating the thermal conductivity according to the measured full width at half maximum and the measured frequency shift is carried out based on Equation (6) and the following equation:

[0120] (11)

[0121] (12)

[0122] (13)

[0123] Where τ is the phonon lifetime, l is the mean free path of phonons, C v is the volumetric specific heat capacity of the wafer, and κ is the thermal conductivity.

[0124] In this embodiment, this application can achieve the detection of thermal conductivity, which is convenient for analyzing the thermal properties of the wafer.

[0125] Second, as Figure 2 and Figure 3 shown, this application provides a spectral detection system, including a laser source 1, a beam splitter 2, a focusing element 3, and a motion mechanism 4 arranged in sequence according to the optical path. The motion mechanism 4 is used to carry and drive the wafer to displace to switch the detection position point;

[0126] The spectral detection system further includes:

[0127] A spectral detection device 5, disposed on one side of the beam splitter 2, for receiving the Brillouin scattered light excited by the laser at the detection position point of the wafer to detect Brillouin spectral information;

[0128] A controller, configured to obtain the measured full width at half maximum and the measured frequency shift according to the Brillouin spectral information during the process of the moving mechanism 4 driving the wafer to displace;

[0129] The controller is further configured to calculate the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, 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.

[0130] The spectral detection system of the present application calculates the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift. Only by exciting the Brillouin scattered light on the wafer can the Brillouin spectral detection be realized, and the crystal defects of the wafer can be detected without damage. And based on the moving mechanism 4 driving the wafer to displace, the present application 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. And the present application detects defects based on the lattice arrangement regularity, and can accurately detect the crystal defects of the wafer.

[0131] 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.

[0132] Preferably, an analyzer 8, a converging lens 9, and a pinhole filter 10 are sequentially arranged between the beam splitter 2 and the spectral detection device 5 according to the optical path.

[0133] In a third aspect, as Figure 4 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. When the electronic device runs, the processor 301 executes the computer program to execute the method in any optional implementation manner of the above embodiment to implement the following functions: obtaining the measured full width at half maximum and the measured frequency shift according to the Brillouin spectral information; calculating the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, 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.

[0134] Fourthly, 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 manner of the above embodiment is executed to implement the following functions: obtaining a measured full width at half maximum and a measured frequency shift according to Brillouin spectrum information; calculating a lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, a standard full width at half maximum, and a standard frequency shift, where the lattice arrangement regularity is used to characterize whether there are crystal defects at the corresponding detection position points 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 (abbreviated as SRAM), electrically erasable programmable read-only memory (abbreviated as EEPROM), erasable programmable read-only memory (abbreviated as EPROM), programmable read-only memory (abbreviated as PROM), read-only memory (abbreviated as ROM), magnetic memory, flash memory, a magnetic disk, or an optical disc.

[0135] In summary, the present application provides a wafer detection method and related devices based on Brillouin spectroscopy. The wafer detection method based on Brillouin spectroscopy provided by the present application calculates the lattice arrangement regularity according to the measured full width at half maximum, the measured frequency shift, the standard full width at half maximum, and the standard frequency shift. Only by exciting Brillouin scattered light on the wafer can Brillouin spectrum detection be realized, and crystal defects of the wafer can be detected nondestructively. Moreover, the present application drives the wafer displacement based on the motion mechanism 4, can quickly perform Brillouin spectrum detection on the wafer, and thus can quickly calculate the lattice arrangement regularity of each detection position point of the wafer 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.

[0136] In the embodiments provided by 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 illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For another 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 displayed or discussed couplings or direct couplings or communication connections to each other can be through some communication interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0137] 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 to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0138] Furthermore, in each embodiment of this application, the various functional modules may be integrated together to form an independent part, or each module may exist alone, or two or more modules may be integrated to form an independent part.

[0139] In this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0140] The above description is only for the embodiments of this application and is not intended to limit the protection scope of this application. For those skilled in the art, this application may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this 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 according to the measured half-width, the measured frequency shift, the standard half-width and the standard frequency shift, wherein the lattice arrangement regularity is used to characterize whether there is a crystal defect at the corresponding detection position of the wafer, and 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 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.

2. 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.

3. The wafer detection method based on Brillouin spectroscopy according to claim 2, 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.

4. 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.

5. The wafer detection method based on Brillouin spectroscopy according to claim 4, 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.

6. 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.

7. 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 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 is a crystal defect at the corresponding detection position point of the wafer. 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 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.

8. 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 6 are performed.

9. 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 6 are performed.

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