Method for improving SHG wafer level detection range and detection rate and SHG measurement platform

Abstract

The invention relates to a multi-thread detection method and system for realizing second harmonic representation based on laser frequency modulation. The method comprises the following steps: splitting a main laser pulse in an incident light path, performing laser modulation to obtain N signal light beams carrying frequency codes, and irradiating a sample after focusing to form a signal light beam carrying an SHG signal in an emergent light path; performing delay control and frequency multiplication on the reference light beam to form a reference light beam carrying an SHG signal; carrying out photoelectric detection and signal splitting on the signal light beam carrying the SHG signal and the reference light beam to obtain N paths of frequency mixing signals; respectively carrying out de-spreading and phase locking on the N paths of frequency mixing signals to obtain frequency deviation values of all paths of signal light beams in the emergent light path; the frequency deviation value is converted into a frequency shift control quantity, and the frequency shift control quantity is fed back to an incident light path for frequency homodyne control of each signal light beam; and after homodyne control, resolving and outputting each path of mixing signal to obtain second harmonic representation of each signal light beam. According to the method, multi-thread detection is realized, and the second harmonic optical characterization performance is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of nonlinear optical characterization, and in particular relates to a method for improving SHG wafer-level detection range and detection rate and an SHG measurement platform. Background Art

[0002] As the feature size of microelectronic devices continues to decrease, the problems caused by defects in wafers are becoming more and more serious. In order to improve the performance, yield and reliability of microelectronic devices, a variety of wafer defect characterization technologies have been developed: optical beam induced current (OBIC) can detect the location of defects, but it depends on special device structures; X-ray diffraction (XRD) can analyze polymorphic dislocations based on diffraction spectra, but it takes a long time to obtain wafer-level defect information; transmission electron microscopy (TEM) can obtain high-resolution defect images, but sample preparation is destructive. Second harmonic generation (SHG) as a fast, non-destructive, non-contact characterization technology has been widely used in the field of wafer-level defect characterization. SHG can be used to locate and identify structural defects such as stacking faults and dislocations on Si wafers.

[0003] Since the excitation wavelength of single-photon absorption is short for wide-bandgap semiconductors, the wavelength range of the second harmonic generated exceeds the wavelength range of 400-1000nm of the most common fiber spectrometer and cannot be effectively detected. In addition, the polarization information generated during second harmonic detection cannot be directly displayed in the spectrum, resulting in reduced SHG's ability and accuracy in characterizing defects. Summary of the invention

[0004] In view of the above analysis, the present invention aims to disclose a method for improving the SHG wafer-level detection range and detection rate and an SHG measurement platform to solve the problems of narrow second harmonic detection range and low detection rate.

[0005] The present invention discloses a method for improving the SHG wafer-level detection range and detection rate, comprising:

[0006] Step S1, polarizing and focusing the fundamental frequency light generated by the laser in the incident light path, obtaining the fundamental frequency light that meets the test conditions and incident on the wafer on the sample stage; the excitation wavelength of the wafer when absorbing single photons is short, and the wavelength range of the generated second harmonic is smaller than the visible light range;

[0007] Step S2, collimating, polarizing and filtering the outgoing light of the wafer in the outgoing light path, and then performing wavelength down-conversion, converting the SHG signal with a wavelength smaller than the visible light range obtained after filtering into a visible light SHG signal with a wavelength in the visible light range; the SHG signal carries wafer defect information;

[0008] Step S3, using a detector to detect visible light SHG signals to obtain SHG characterization;

[0009] Step S4, moving the sample stage to scan and detect the wafer, splicing the detected SHG characterization according to the scanning data points, and obtaining the defect information of the entire wafer; detecting the SHG characterization under various incident angles and performing quantitative analysis of the defect information.

[0010] Furthermore, the wafer for SHG characterization detection is a wide bandgap semiconductor including SiC, GaN and diamond.

[0011] Further, in step S2, the SHG signal with a wavelength smaller than the visible light range obtained after filtering is converted into a low-energy visible light SHG signal after wavelength down-conversion and focusing by a down-conversion fluorescent crystal;

[0012] The down-conversion fluorescent crystal comprises a down-conversion fluorescent material and a focusing lens; wherein the down-conversion fluorescent material is Sn-doped silicate fluorescent glass and fluorescent dye-doped polystyrene.

[0013] Furthermore, in step S4, a Mapping scanning method is adopted to control the movement of the sample stage to scan and detect the wafer, and the detected SHG characterization is spliced ​​according to the scanning data points to obtain the defect information of the entire wafer;

[0014] By controlling the instruments on the incident light path to cooperate with the instruments on the outgoing light path, the incident angle of the incident light path is changed; the SHG characterization is measured at different angles to perform quantitative analysis on the defect information.

[0015] The present invention also discloses an SHG measurement platform, comprising: an incident light path unit, an exit light path unit, a sample stage and a wafer; wherein:

[0016] The wafer is fixed on the sample stage; the excitation wavelength of the wafer when absorbing a single photon is short, and the wavelength range of the generated second harmonic is smaller than the visible light range;

[0017] An incident light path unit is used to polarize and focus the fundamental frequency light generated by the laser in the incident light path, so as to obtain the fundamental frequency light that meets the test conditions and is incident on the wafer on the sample stage;

[0018] The output optical path unit is used to receive the output light reflected by the wafer, and after collimation, polarization analysis and filtering, the wavelength is converted down to convert the SHG signal with a wavelength smaller than the visible light range obtained after filtering into a visible light SHG signal with a wavelength in the visible light range; the visible light SHG signal is then detected to obtain SHG characterization.

[0019] Furthermore, the incident light path unit includes: a laser, a polarizer and an incident objective lens in sequence from the generation of the fundamental frequency light to the irradiation of the wafer;

[0020] The laser is used to generate fundamental frequency light;

[0021] The polarizer is used to add set polarization information to the fundamental frequency light;

[0022] The incident objective lens is used to focus the fundamental frequency light with the set polarization information added thereto, so as to obtain the fundamental frequency light meeting the test conditions and irradiate the wafer on the sample stage.

[0023] Furthermore, the output light path unit includes, in sequence, an output objective lens, an analyzer, a filter, a down-conversion fluorescent crystal and a detector, along the output light reflected from the wafer to the detection of SHG characterization;

[0024] The output objective lens is used to collimate the output light reflected by the wafer;

[0025] The polarizer is used to analyze the collimated outgoing light to obtain outgoing light with a set polarization state;

[0026] The filter is used to filter the outgoing light of the set polarization state, filter out the fundamental frequency light, and obtain the SHG signal carrying the wafer defect information;

[0027] The down-conversion fluorescent crystal is used to convert the SHG signal carrying the wafer defect information obtained after filtering from a wavelength less than the visible light range into a visible light SHG signal with a wavelength in the visible light range;

[0028] The detector detects visible light SHG signals to obtain SHG characterization.

[0029] Furthermore, the down-conversion fluorescent crystal includes a down-conversion fluorescent material and a focusing lens; wherein,

[0030] The down-conversion fluorescent material can down-convert the SHG signal in frequency on the one hand, and can also be polarization-sensitive, converting the SHG signal with a wavelength smaller than the visible light range into the visible light range, thereby obtaining a visible light SHG signal with polarization information.

[0031] The down-conversion fluorescent materials are Sn-doped silicate fluorescent glass and fluorescent dye-doped polystyrene.

[0032] Furthermore, it also includes an arc guide rail, an incident arm and an exit arm; the arc guide rail is slidably equipped with the incident arm and the exit arm, the incident arm and the exit arm respectively serve as supporting structures of the incident light path unit and the exit light path unit, and both can slide on the arc guide rail around the sample stage, the arc guide rail is located directly above the sample stage, and the arc guide rail is used to control the positions of the incident arm and the exit arm, thereby determining the incident angle of the incident light;

[0033] By controlling the positions of the incident arm and the exit arm on the arc guide rail, the incident angle of the incident light path is changed; the SHG characterization is measured at different angles to perform quantitative analysis of the defect information.

[0034] Furthermore, it also includes a control unit, which controls the sample stage to drive the wafer to move, performs mapping scanning on the wafer, and detects defects at different positions of the wafer; and splices the acquired data points to obtain defect information of the entire wafer.

[0035] The present invention can achieve one of the following beneficial effects:

[0036] The method for improving the SHG wafer-level detection range and detection rate and the SHG measurement platform of the present invention utilize down-conversion fluorescent materials to convert near-ultraviolet and ultraviolet SHG spectra into the visible light range, thereby broadening the detection range and improving the detection accuracy. Polarization information can be directly detected, and the entire wafer defect information can be more accurately acquired during Mapping scanning, thereby ultimately improving the SHG characterization accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. In the entire drawings, the same reference symbols represent the same components;

[0038] Figure 1 A flow chart of a method for improving SHG wafer-level detection range and detection rate in an embodiment of the present invention;

[0039] Figure 2 Analytical diagram of the excitation spectrum and emission spectrum of the Sn-doped silicate fluorescent glass sample in the embodiment of the present invention;

[0040] Figure 3 It is a schematic diagram of the connection components of the SHG measurement platform in an embodiment of the present invention.

[0041] Figure numerals: 1-laser, 2-polarizer, 3-incident objective lens, 4-fundamental frequency light that meets the test conditions, 5-exit objective lens, 6-polarizer, 7-filter, 8-second harmonic beam carrying defect information, 9-detector, 10-wafer, 11-sample stage, 12-down-conversion fluorescent crystal. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used to illustrate the principles of the present invention together with the embodiments of the present invention.

[0043] Embodiment 1

[0044] One embodiment of the present invention discloses a method for improving the SHG wafer-level detection range and detection rate, such as Figure 1As shown, including:

[0045] Step S1, polarizing and focusing the fundamental frequency light generated by the laser in the incident light path, obtaining the fundamental frequency light that meets the test conditions and incident on the wafer on the sample stage;

[0046] The excitation wavelength of the wafer when absorbing a single photon is short, and the wavelength range of the generated second harmonic is smaller than the visible light range;

[0047] Step S2, collimating, polarizing and filtering the outgoing light of the wafer in the outgoing light path, and then performing wavelength down-conversion, converting the SHG signal with a wavelength smaller than the visible light range obtained after filtering into a visible light SHG signal with a wavelength in the visible light range; the SHG signal carries wafer defect information;

[0048] Step S3, using a detector to detect visible light SHG signals to obtain SHG characterization;

[0049] Step S4, moving the sample stage to scan and detect the wafer, splicing the detected SHG characterization according to the scanning data points, and obtaining the defect information of the entire wafer; detecting the SHG characterization under various incident angles and performing quantitative analysis of the defect information.

[0050] Specifically, the wafer is a wide bandgap semiconductor including SiC, GaN and diamond. The excitation wavelength during single-photon absorption is short, and the wavelength range of the generated second harmonic is in the ultraviolet spectrum range, which exceeds the wavelength range of 400-1000nm of the most common fiber spectrometer currently.

[0051] In step S1, a laser generates fundamental frequency light, and a polarization information is added to the fundamental frequency light through a polarizer; the fundamental frequency light with the polarization information added is focused through an incident objective lens to obtain fundamental frequency light that meets the test conditions and irradiates the wafer on the sample stage.

[0052] Specifically, in step S2, the outgoing light reflected by the wafer is collimated by the outgoing objective lens; the collimated outgoing light is polarized by the analyzer to obtain the outgoing light of the set polarization state; the outgoing light of the set polarization state is filtered by the filter to filter out the fundamental frequency light, and the SHG signal carrying the wafer defect information is obtained;

[0053] Specifically, in step S2, the SHG signal with a wavelength smaller than the visible light range obtained after filtering is high-energy near-ultraviolet light and ultraviolet light; the SHG signals of near-ultraviolet light and ultraviolet light cannot be detected by the spectrometer.

[0054] After wavelength down-conversion and focusing by a down-conversion fluorescent crystal, the high-energy near-ultraviolet and ultraviolet SHG signals with wavelengths smaller than the visible light range obtained after filtering are converted into low-energy visible light SHG signals;

[0055] Preferably, the down-conversion fluorescent crystal comprises a down-conversion fluorescent material and a focusing lens; wherein the down-conversion fluorescent material is Sn-doped silicate fluorescent glass and fluorescent dye-doped polystyrene;

[0056] After wavelength down-conversion and focusing through the down-conversion fluorescent crystal, the generated second harmonic signal can be converted into visible light of 550-700nm; the converted visible light SHG signal can be indirectly measured by the fiber optic spectrometer, thereby widening the detection range of the original fiber optic spectrometer.

[0057] Furthermore, by incidenting the SHG signal with polarization information onto the down-conversion fluorescent material crystal, the down-conversion fluorescent crystal becomes polarization sensitive and obtains the SHG signal with polarization information, thereby improving the characterization capability and accuracy of SHG.

[0058] like Figure 2 As shown, it is an analysis diagram of the excitation spectrum and emission spectrum of Sn-doped silicate fluorescent glass. It can be observed from the figure that the sample converts ultraviolet light in the ultraviolet spectrum into visible light of 550-700nm.

[0059] Specifically, in step S4, a Mapping scanning method is adopted to control the movement of the sample stage to scan and detect the wafer, and the detected SHG characterization is spliced ​​according to the scanning data points to obtain the defect information of the entire wafer;

[0060] By controlling the instruments on the incident light path to cooperate with the instruments on the outgoing light path, the incident angle of the incident light path is changed; the SHG characterization is measured at different angles to perform quantitative analysis on the defect information.

[0061] More specifically, in step S4, the arc guide rail, the incident arm and the exit arm control the instruments on the incident light path to cooperate with the instruments on the exit light path to change the incident angle of the incident light path; the SHG characterization is measured at different angles to further perform quantitative analysis on the defect information;

[0062] The arc guide rail is slidably equipped with an incident arm and an exit arm, which serve as supporting structures of the incident light path unit and the exit light path unit respectively, and can slide on the arc guide rail around the sample stage. The arc guide rail is located directly above the sample stage, and is used to control the positions of the incident arm and the exit arm, thereby determining the incident angle of the incident light;

[0063] By controlling the positions of the incident arm and the exit arm on the arc guide rail, the incident angle of the incident light path is changed; the SHG characterization is measured at different angles to further perform quantitative analysis of the defect information.

[0064] Specifically, in step S4, a Mapping scanning method is used to control the movement of the sample stage, and defects at different positions of the wafer corresponding to each moving point are synchronously detected; the acquired data points are spliced ​​to obtain the defect information of the entire wafer.

[0065] In summary, the method for improving the SHG wafer-level detection range and detection rate and the SHG measurement platform disclosed in the embodiments of the present invention utilize down-conversion fluorescent materials to convert near-ultraviolet and ultraviolet SHG spectra into the visible light range, thereby broadening the detection range and improving the detection accuracy. Polarization information can also be directly detected, and the entire wafer defect information can be more accurately acquired during Mapping scanning, thereby ultimately improving the SHG characterization accuracy.

[0066] Embodiment 2

[0067] This embodiment discloses a SHG measurement platform, such as Figure 3 As shown, it includes: an incident light path unit, an output light path unit, a sample stage and a wafer; wherein,

[0068] The wafer is fixed on the sample stage; the excitation wavelength of the wafer when absorbing a single photon is short, and the wavelength range of the generated second harmonic is smaller than the visible light range;

[0069] An incident light path unit is used to polarize and focus the fundamental frequency light generated by the laser in the incident light path, so as to obtain the fundamental frequency light that meets the test conditions and is incident on the wafer on the sample stage;

[0070] The output optical path unit is used to receive the output light reflected by the wafer, and after collimation, polarization analysis and filtering, the wavelength is converted down to convert the SHG signal with a wavelength smaller than the visible light range obtained after filtering into a visible light SHG signal with a wavelength in the visible light range; the visible light SHG signal is then detected to obtain SHG characterization.

[0071] Specifically, the wafer is a wide bandgap semiconductor including SiC, GaN and diamond. The excitation wavelength during single-photon absorption is short, and the wavelength range of the generated second harmonic is in the ultraviolet spectrum range, which exceeds the wavelength range of 400-1000nm of the most common fiber spectrometer currently.

[0072] Specifically, the incident light path unit includes: a laser, a polarizer and an incident objective lens in sequence from the generation of fundamental frequency light to the irradiation of the wafer;

[0073] The laser is used to generate fundamental frequency light;

[0074] The polarizer is used to add set polarization information to the fundamental frequency light;

[0075] The incident objective lens is used to focus the fundamental frequency light with the set polarization information added thereto, so as to obtain the fundamental frequency light meeting the test conditions and irradiate the wafer on the sample stage.

[0076] Specifically, the output light path unit includes, in sequence, an output objective lens, an analyzer, a filter, a down-conversion fluorescent crystal and a detector, along the output light reflected by the wafer to the detection of SHG characterization;

[0077] The output objective lens is used to collimate the output light reflected by the wafer;

[0078] The polarizer is used to analyze the collimated outgoing light to obtain outgoing light with a set polarization state;

[0079] The filter is used to filter the outgoing light of the set polarization state, filter out the fundamental frequency light, and obtain the SHG signal carrying the wafer defect information;

[0080] The down-conversion fluorescent crystal is used to convert the SHG signal carrying the wafer defect information obtained after filtering from a wavelength less than the visible light range into a visible light SHG signal with a wavelength in the visible light range;

[0081] The detector is used to detect visible light SHG signals to obtain SHG characterization.

[0082] Preferably, the detector is a fiber optic spectrometer.

[0083] Specifically, the down-conversion fluorescent crystal includes a down-conversion fluorescent material and a focusing lens; wherein the down-conversion fluorescent material is Sn-doped silicate fluorescent glass and fluorescent dye-doped polystyrene;

[0084] After wavelength down-conversion and focusing of the down-conversion fluorescent crystal, the generated second harmonic signal can be converted into visible light of 550-700nm; the SHG signal converted into visible light can be indirectly measured by the fiber optic spectrometer, thereby widening the detection range of the original fiber optic spectrometer. In addition, by incidenting the SHG signal with polarization information on the down-conversion fluorescent material crystal, the down-conversion fluorescent crystal shows polarization sensitivity, and obtains the SHG signal with polarization information, thereby improving the characterization ability and accuracy of SHG.

[0085] Specifically, it also includes a control unit; the control unit controls the sample stage to drive the wafer to move, performs mapping scanning on the wafer, and detects defects at different positions of the wafer; and splices the acquired data points to obtain defect information of the entire wafer.

[0086] Preferably, it further comprises an arc guide rail, an incident arm and an exit arm; the arc guide rail is slidably equipped with the incident arm and the exit arm, the incident arm and the exit arm respectively serve as supporting structures of the incident light path unit and the exit light path unit, and both can slide on the arc guide rail around the sample stage, the arc guide rail is located directly above the sample stage, and the arc guide rail is used to control the positions of the incident arm and the exit arm, thereby determining the incident angle of the incident light;

[0087] By controlling the positions of the incident arm and the exit arm on the arc guide rail, the incident angle of the incident light path is changed; the SHG characterization is measured at different angles to further perform quantitative analysis of the defect information.

[0088] In summary, this embodiment discloses an SHG measurement platform, which uses down-conversion fluorescent materials to convert near-ultraviolet and ultraviolet SHG spectra into the visible light range, broadens the detection range, improves the detection accuracy, and can directly detect polarization information, more accurately obtain the entire wafer defect information in Mapping scanning, and ultimately improves the SHG characterization accuracy.

[0089] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for improving SHG wafer-level detection range and detection rate, characterized in that: include: Step S1, polarizing and focusing the fundamental frequency light generated by the laser in the incident light path, obtaining the fundamental frequency light that meets the test conditions and incident on the wafer on the sample stage; The excitation wavelength of the wafer when absorbing a single photon is short, and the wavelength range of the generated second harmonic is smaller than the visible light range; Step S2, collimating, polarizing and filtering the outgoing light of the wafer in the outgoing light path, and then performing wavelength down-conversion, converting the SHG signal with a wavelength smaller than the visible light range obtained after filtering into a visible light SHG signal with a wavelength in the visible light range; the SHG signal carries wafer defect information; Step S3, using a detector to detect visible light SHG signals to obtain SHG characterization; Step S4, moving the sample stage to scan and detect the wafer, splicing the detected SHG characterization according to the scanning data points, and obtaining the defect information of the entire wafer; SHG characterization is detected under various incident angles to perform quantitative analysis of defect information.

2. The method for improving SHG wafer-level detection range and detection rate according to claim 1, characterized in that: The wafer for SHG characterization detection is a wide bandgap semiconductor including SiC, GaN and diamond.

3. The method for improving SHG wafer-level detection range and detection rate according to claim 2, characterized in that: In step S2, the SHG signal with a wavelength smaller than the visible light range obtained after filtering is converted into a low-energy visible light SHG signal after wavelength down-conversion and focusing by a down-conversion fluorescent crystal; The down-conversion fluorescent crystal comprises a down-conversion fluorescent material and a focusing lens; wherein the down-conversion fluorescent material is Sn-doped silicate fluorescent glass and fluorescent dye-doped polystyrene.

4. The method for improving SHG wafer-level detection range and detection rate according to claim 3, characterized in that: In step S4, a Mapping scanning method is adopted to control the movement of the sample stage to scan and detect the wafer, and the detected SHG characterization is spliced ​​according to the scanning data points to obtain the defect information of the entire wafer; By controlling the instruments on the incident light path to cooperate with the instruments on the outgoing light path, the incident angle of the incident light path is changed; the SHG characterization is measured at different angles to perform quantitative analysis on the defect information.

5. A SHG measurement platform, characterized in that: include: An incident light path unit, an output light path unit, a sample stage and a wafer; wherein, The wafer is fixed on the sample stage; the excitation wavelength of the wafer when absorbing a single photon is short, and the wavelength range of the generated second harmonic is smaller than the visible light range; An incident light path unit is used to polarize and focus the fundamental frequency light generated by the laser in the incident light path, so as to obtain the fundamental frequency light that meets the test conditions and is incident on the wafer on the sample stage; The output optical path unit is used to receive the output light reflected by the wafer, and after collimation, polarization analysis and filtering, the wavelength is converted down to convert the SHG signal with a wavelength smaller than the visible light range obtained after filtering into a visible light SHG signal with a wavelength in the visible light range; the visible light SHG signal is then detected to obtain SHG characterization.

6. The SHG measurement platform according to claim 5, characterized in that: The incident light path unit includes: a laser, a polarizer and an incident objective lens in sequence from the generation of fundamental frequency light to the irradiation of the wafer; The laser is used to generate fundamental frequency light; The polarizer is used to add set polarization information to the fundamental frequency light; The incident objective lens is used to focus the fundamental frequency light with the set polarization information added thereto, so as to obtain the fundamental frequency light meeting the test conditions and irradiate the wafer on the sample stage.

7. The SHG measurement platform according to claim 5, characterized in that: The output light path unit includes, in sequence, an output objective lens, an analyzer, a filter, a down-conversion fluorescent crystal and a detector, along the output light reflected by the wafer to the detection of SHG characterization; The output objective lens is used to collimate the output light reflected by the wafer; The polarizer is used to analyze the collimated outgoing light to obtain outgoing light with a set polarization state; The filter is used to filter the outgoing light of the set polarization state, filter out the fundamental frequency light, and obtain the SHG signal carrying the wafer defect information; The down-conversion fluorescent crystal is used to convert the SHG signal carrying the wafer defect information obtained after filtering from a wavelength less than the visible light range into a visible light SHG signal with a wavelength in the visible light range; The detector performs visible light SHG signal detection to obtain SHG characterization.

8. The SHG measurement platform according to claim 7, characterized in that: The down-conversion fluorescent crystal includes a down-conversion fluorescent material and a focusing lens; wherein, The down-conversion fluorescent material can down-convert the SHG signal in frequency on the one hand, and can also be polarization-sensitive, converting the SHG signal with a wavelength smaller than the visible light range into the visible light range, thereby obtaining a visible light SHG signal with polarization information. The down-conversion fluorescent material is Sn-doped silicate fluorescent glass and fluorescent dye-doped polystyrene.

9. The SHG measurement platform according to any one of claims 5 to 8, characterized in that: It also includes an arc guide rail, an incident arm and an exit arm; the arc guide rail is slidably equipped with the incident arm and the exit arm, the incident arm and the exit arm respectively serve as supporting structures of the incident light path unit and the exit light path unit, and both can slide on the arc guide rail around the sample stage, the arc guide rail is located directly above the sample stage, and the arc guide rail is used to control the positions of the incident arm and the exit arm, thereby determining the incident angle of the incident light; By controlling the positions of the incident arm and the exit arm on the arc guide rail, the incident angle of the incident light path is changed; the SHG characterization is measured at different angles to perform quantitative analysis of the defect information.

10. The SHG measurement platform according to claim 9, characterized in that: It also includes a control unit, which controls the sample stage to drive the wafer to move, performs mapping scanning on the wafer, and detects defects at different positions of the wafer; and splices the acquired data points to obtain defect information of the entire wafer.

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