A method of second harmonic measurement and a measuring instrument

Abstract

The application discloses a second harmonic measurement method and a measuring instrument. The method comprises the following steps: obtaining a first light spot area formed by an incident laser beam irradiating on a sample to be measured at a first incident angle; obtaining a standard optical power density according to the first light spot area and a first optical parameter; obtaining a second light spot area formed by the incident laser beam irradiating on the sample to be measured at a second incident angle; obtaining a target optical parameter according to the standard optical power density and the second light spot area; and obtaining a second harmonic intensity per unit light spot area under the condition of the second incident angle and the target optical parameter. The test precision can be improved, and the test error can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material testing, in particular to a second harmonic measurement method and a measuring instrument. BACKGROUND

[0002] Traditional methods for testing defects of semiconductor materials usually include capacitance voltage method (C-V method) and X-ray diffraction method, and the testing instruments used usually include transmission electron microscope and atomic force microscope. However, the above testing methods or testing instruments all need to additionally prepare a testing sample, the testing time is long, non-contact testing cannot be realized, the sample will be damaged in the testing process, and wafer-level testing cannot be performed. As a new testing technology, the second harmonic (SHG) testing method can utilize the nonlinear effect of light interaction with semiconductor materials to non-contact, fast, lossless, wafer-level and online test the defects of semiconductor materials.

[0003] However, in the second harmonic testing method, the testing light is irradiated onto the testing sample, and the testing result is obtained by receiving and analyzing the second harmonic in the reflected light, which is affected by many factors, has low measurement accuracy and large error. SUMMARY

[0004] The second harmonic measurement method and the measuring instrument provided by the embodiments of the present application can improve the testing accuracy and reduce the testing error.

[0005] In a first aspect, a second harmonic measurement method comprises:

[0006] obtaining a first light spot area formed by an incident laser beam irradiated on a to-be-tested sample at a first incident angle;

[0007] obtaining a standard optical power density according to the first light spot area and a first optical parameter;

[0008] obtaining a second light spot area formed by the incident laser beam irradiated on the to-be-tested sample at a second incident angle;

[0009] obtaining a target optical parameter according to the standard optical power density and the second light spot area;

[0010] obtaining a unit light spot area second harmonic intensity under the condition of the second incident angle and the target optical parameter.

[0011] In a feasible implementation, the first optical parameter comprises a first polarization direction included angle, and the first polarization direction included angle is an included angle formed by a first polarization direction of an adjustable polarization unit and a polarization direction of a polarizing unit.

[0012] The step of obtaining the standard optical power density according to the first spot area and the first optical parameter comprises:

[0013] obtaining a first angle between a transmission vibration direction and the incident laser beam;

[0014] calculating the standard optical power density ρ0 according to the following formula:

[0015]

[0016] wherein α0 is the first angle between the transmission vibration direction, P is the initial optical power, and S0 is the first spot area.

[0017] In an embodiment, the target optical parameter comprises a target angle between a second transmission vibration direction of the adjustable polarization unit and a transmission vibration direction of the polarizing unit.

[0018] The step of obtaining the target optical parameter according to the standard optical power density and the second spot area comprises:

[0019] calculating the target angle between the transmission vibration direction α1 according to the standard optical power density and the second spot area according to the following formula:

[0020]

[0021] wherein P is the initial optical power of the incident laser beam, S is the second spot area, and ρ0 is the standard optical power density.

[0022] In an embodiment, the step of obtaining the second harmonic intensity per unit spot area under the condition of the second incident angle and the target optical parameter comprises:

[0023] adjusting the transmission vibration direction of the adjustable polarization unit so that the second angle between the transmission vibration direction is the same as the target angle between the transmission vibration direction;

[0024] obtaining the second harmonic intensity per unit spot area under the condition of the second incident angle and the target optical parameter.

[0025] In an embodiment, the step of obtaining the second harmonic intensity per unit spot area under the condition of the second incident angle and the target optical parameter comprises:

[0026] obtaining the second harmonic intensity under the condition of the second incident angle and the target optical parameter;

[0027] According to the second harmonic intensity and the second spot area, the unit spot area second harmonic intensity LS under the condition of the second incidence angle and the target optical parameter is calculated according to the following formula:

[0028]

[0029] Wherein, L is the second harmonic intensity, and S is the second spot area.

[0030] In a second aspect, a second harmonic measuring instrument comprises a laser emission assembly, an incident light path optical assembly, a detection light path optical assembly, a detection assembly, and an image acquisition assembly.

[0031] The incident light path optical assembly is configured to form the laser beam emitted by the laser emission assembly into an incident laser beam directed towards a sample to be measured.

[0032] The detection light path optical assembly is configured to receive the second harmonic reflected by the sample to be measured to the detection assembly.

[0033] The image acquisition assembly is configured to acquire a spot area irradiated on the sample to be measured.

[0034] The incident light path optical assembly comprises an incident optical power adjustment unit configured to adjust an optical parameter according to the spot area to adjust the optical power of the incident laser beam irradiated on the sample to be measured.

[0035] In an available embodiment, the incident optical power adjustment unit comprises a polarizing unit and an adjustable polarizing unit arranged oppositely, and the transmission direction of the adjustable polarizing unit is adjustable.

[0036] The optical parameter comprises an included angle formed between the transmission direction of the adjustable polarizing unit and the transmission direction of the polarizing unit.

[0037] The detection light path optical assembly comprises a detection polarizing unit.

[0038] In an available embodiment, the adjustable polarizing unit comprises a polarizing plate and a stepping motor in transmission connection with the polarizing plate.

[0039] The stepping motor is configured to drive the polarizing plate to rotate to adjust the transmission direction of the polarizing plate.

[0040] In an available embodiment, the image acquisition assembly is arranged between the incident light path optical assembly and the detection light path optical assembly.

[0041] In an implementable embodiment, the incident light path optical assembly further comprises a focusing objective lens, which is arranged on the side of the incident optical power adjusting unit away from the laser emitting assembly.

[0042] The probe light path optical assembly further comprises a collimating objective lens and a filter, which is arranged between the collimating objective lens and the probe assembly.

[0043] The second harmonic measurement method and the measurement instrument provided by the embodiments of the present application can obtain the standard optical power density by taking the spot area into account, and the standard optical power density can be used as the standard for reference of other test points of the same sample. The target optical parameter is obtained by the standard optical power density and the spot area of the corresponding test point, the optical parameter corresponding to the current test point is adjusted accordingly, and the unit spot area second harmonic intensity corresponding to the current test point is obtained. The unit spot area second harmonic intensity is used as the final test data. In this way, the influence of the spot area can be removed, and the problem that when the spot area changes with the incident angle, the laser power density irradiated on the sample to be tested changes, the second harmonic intensity with the defect information of the sample to be tested is affected, and the detection accuracy of the defect information of the sample to be tested is affected can be solved. Therefore, the second harmonic measurement method provided by the embodiments of the present application can improve the test accuracy and reduce the test error. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 A schematic flowchart of a second harmonic measurement method provided by the embodiments of the present application is shown in the figure;

[0045] Figure 2 A schematic diagram of a vertically incident laser Gaussian beam provided by the embodiments of the present application is shown in the figure;

[0046] Figure 3 A schematic diagram of an obliquely incident laser Gaussian beam provided by the embodiments of the present application is shown in the figure;

[0047] Figure 4 A schematic diagram of the obtained second harmonic intensity changing with the incident angle provided by the embodiments of the present application is shown in the figure;

[0048] Figure 5 A structural schematic diagram of a second harmonic measurement instrument provided by the embodiments of the present application is shown in the figure;

[0049] Figure 6 A structural schematic diagram of another second harmonic measurement instrument provided by the embodiments of the present application is shown in the figure. DETAILED DESCRIPTION

[0050] In order to better understand the technical solutions provided by the embodiments of the present specification, the technical solutions of the embodiments of the present specification will be described in detail below through the accompanying drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present specification and the embodiments are detailed descriptions of the technical solutions of the present specification, and are not limitations of the technical solutions of the present specification. In the case of no conflict, the technical features in the embodiments of the present specification and the embodiments can be combined with each other.

[0051] In this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises... " does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element. The term "two or more" includes two or more than two.

[0052] The conventional method for testing defects of semiconductor materials usually has a capacitance voltage method and an X-ray diffraction method, and the test instruments used usually have a transmission electron microscope and an atomic force microscope. However, the above test methods or test instruments all need to prepare test samples additionally, the test time is long, non-contact testing cannot be realized, the sample will be damaged in the test process, and wafer-level testing cannot be performed. As a new test technology, the SHG test method can utilize the nonlinear effect of light interaction with semiconductor materials to non-contact, fast, non-destructive, wafer-level and online test the defects of semiconductor materials. However, in the second harmonic test method, the test light is irradiated onto the test sample, and the test result is obtained by receiving and analyzing the second harmonic in the reflected light. The spot area irradiated on the sample will change with the incident angle of the incident light, the intensity of the received second harmonic will change with the change of the spot area, and then the test result will be affected by the change of the second harmonic intensity, resulting in a large test error.

[0053] Therefore, in a first aspect, Figure 1 A schematic flowchart of a second harmonic measurement method provided by an embodiment of the present application is shown in FIG. 1. As shown in the figure, the second harmonic measurement method provided by the embodiment of the present application comprises the following steps. Figure 1

[0054] ​S100: Obtain a first spot area formed by an incident laser beam at a first incident angle on a sample to be measured. In the second harmonic measurement method, the incident laser beam is incident on the sample to be measured, and reflected light is generated. Due to the optical properties of the film layer of the sample to be measured and the defects on or in the film layer, frequency doubling occurs during the reflection of the incident laser beam, thereby generating a second harmonic. The fundamental wave of the second harmonic is the incident laser beam incident on the sample to be measured. It can be understood that the spot area formed on the sample to be measured is different when the incident laser beam is incident on the sample to be measured at different incident angles. The incident angle can be achieved by changing the angle of the incident light path. Figure 2 A schematic diagram of a vertically incident laser Gaussian beam provided by an embodiment of the present application is shown in FIG. 1. Figure 3 A schematic diagram of an obliquely incident laser Gaussian beam provided by an embodiment of the present application is shown in FIG. 2. Figure 2 As shown in FIG. 1, the incident laser beam is usually a Gaussian beam. When the incident laser Gaussian beam L is vertically incident on the sample to be measured, a spot F1 is formed on the sample plane M. Figure 2 As shown in FIG. 2, when the incident laser Gaussian beam L is obliquely incident on the sample to be measured, a spot F2 is formed on the sample plane M. Obviously, the spot area of the oblique incidence is larger than that of the vertical incidence. When the spot areas are different, the optical power incident on the sample to be measured is also different, which further affects the second harmonic intensity with the defect information of the sample to be measured, and then affects the detection accuracy of the defect information of the sample to be measured. Therefore, the second harmonic measurement method provided by the embodiment of the present application takes the spot area into account.

[0055] S200: Obtain a standard optical power density according to the first spot area and the first optical parameter. The first incident angle, the first spot area, and the first optical parameter can be taken as standard incident conditions, and the optical power density incident on the sample to be measured under the standard incident conditions can be taken as the standard optical power density. In the subsequent testing process of other points of the same sample to be measured, the standard optical power density can be taken as a standard value for reference.

[0056] S300: Obtain a second spot area formed by an incident laser beam at a second incident angle on a sample to be measured. The other points of the sample to be measured can be tested by moving the sample stage or moving the incident light path, and the second spot area formed by the incident laser beam at the second incident angle on the sample to be measured is obtained. The second spot area can represent the spot area corresponding to any incident angle.

[0057] S400: Obtain a target optical parameter according to the standard optical power density and the second spot area. The target optical parameter is obtained according to the second spot area with reference to the standard optical power density. The standard optical power density and the second spot area can be taken as known quantities, and the target optical parameter can be calculated.

[0058] S500: Obtain the unit spot area second harmonic intensity under the second incidence angle and the target optical parameter condition. It can be understood that the second harmonic intensity under the second incidence angle and the target optical parameter condition is obtained first, and then the unit spot area second harmonic intensity is calculated according to the second spot area.

[0059] It can be understood that the incidence angle of the incident laser beam irradiated on the sample to be measured can be continuously changed, for example, the incidence angle can be 20-70°, and the first incidence angle is only a standard optical power density corresponding incidence angle, which can be any angle in the range of 20-70°, which can be 45°, or 30°, and the present application is not limited to the specific. The second incidence angle represents the possible incidence angle of other test points on the sample to be measured or different incidence angles of the same test point after obtaining the standard optical power density. For example, Figure 4 The obtained second harmonic intensity changes with the incidence angle provided by the embodiment of the present application, Figure 4 The abscissa is the incidence angle, and the ordinate is the value of the obtained second harmonic intensity data after normalization processing, Figure 4 The relationship between the normalized second harmonic intensity and the incidence angle of two samples to be measured is shown, Figure 4 which can be obtained by actual data measurement.

[0060] The second harmonic measurement method and measuring instrument provided by the embodiment of the present application considers the spot area, first obtains the standard optical power density as the standard for subsequent other test points of the same sample, obtains the target optical parameter through the standard optical power density and the spot area of the corresponding test point, adjusts the optical parameter corresponding to the current test point, and finally obtains the unit spot area second harmonic intensity corresponding to the current test point. The unit spot area second harmonic intensity is used as the final test data. In this way, the influence of the spot area can be removed, and the problem that when the spot area changes with the incidence angle, the laser power density irradiated on the sample to be measured changes, which affects the second harmonic intensity of the sample to be measured and further affects the detection precision of the defect information of the sample to be measured. Therefore, the second harmonic measurement method provided by the embodiment of the present application can improve the test precision and reduce the test error.

[0061] In an implementation, the first optical parameter includes a first pass direction angle, which is an angle formed between a pass direction of the first adjustable polarization unit and a pass direction of the polarizing unit. The optical parameter can be a pass direction angle, which is formed by two polarization units, specifically, one is a polarizing unit with a fixed pass angle, and the other is an adjustable polarization unit with an adjustable pass direction. The change of the pass direction angle can change the optical power of the incident laser beam. It can be understood that the larger the pass direction angle, the smaller the optical power of the transmitted light, and vice versa. Therefore, adjusting the pass direction angle can adjust the size of the transmitted optical power, so as to adjust the optical power on the sample to be measured. The first incident angle corresponds to the first spot area, and the first optical parameter corresponds to the first pass direction angle. The first spot area, the first pass direction angle, and the optical power of the laser beam emitted by the laser emitting assembly can determine the optical power density on the sample to be measured.

[0062] Step S200: obtaining a standard optical power density according to the first spot area and the first optical parameter, which can include:

[0063] obtaining the first pass direction angle and an initial optical power of the incident laser beam;

[0064] calculating the standard optical power density p0 according to the following formula:

[0065]

[0066] wherein a0 is the first pass direction angle, P is the initial optical power, and S0 is the first spot area. The initial optical power of the incident laser beam is the optical power of the laser beam emitted by the laser source. The laser source referred to in the following of the present application can be the laser emitting assembly, which is not described herein.

[0067] According to different requirements of the laser emitting assembly or design specifications, the initial optical power can be constant. The initial optical power emitted by the laser emitting assembly can be monitored in a set period, which can reduce the calculation amount. The standard optical power density can be updated regularly, and the same sample to be measured can only calculate the standard optical power density once, or a group of samples to be measured can calculate the standard optical power density once. The number of samples to be measured in a group can be 5, 10 or other numbers, which are not limited in the present application.

[0068] The secondary harmonic wave measurement method provided in the embodiments of the present application can change the optical power irradiated on the to-be-tested sample by adjusting the optical parameter, and the adjustment of the optical parameter can be realized by adjusting the first and second transparent vibration direction included angles, which is simple to operate and easy to realize. The embodiments of the present application give the specific calculation formula of the standard optical power density, and the standard optical power density calculated by taking the first light spot area and the first optical parameter into account can be used as the reference standard for subsequent tests, which can solve the problem that when the light spot area changes with the change of the incident angle, the optical power irradiated on the to-be-tested sample also changes, which further affects the secondary harmonic wave intensity with the defect information of the to-be-tested sample, and then affects the detection precision of the defect information of the to-be-tested sample.

[0069] In a feasible implementation, the target optical parameter includes a target transparent vibration direction included angle, and the target transparent vibration direction included angle is an included angle formed by the second transparent vibration direction of the adjustable polarization unit and the transparent vibration direction of the polarizing unit.

[0070] Step S400: obtaining a target optical parameter according to the standard optical power density and the second light spot area, including:

[0071] According to the standard optical power density and the second light spot area, the target transparent vibration direction included angle α1 is calculated according to the following formula:

[0072]

[0073] Wherein, P is the initial optical power, S is the second light spot area, and ρ0 is the standard optical power density.

[0074] The secondary harmonic wave measurement method provided in the embodiments of the present application takes the standard optical power density as the reference standard, that is, by adjusting the optical parameter, the optical power density irradiated on any test point of the to-be-tested sample under different incident angles is ensured to be the same, so that the target optical parameter can be inversely deduced according to the same value of the standard optical power density and the second light spot area corresponding to the current test point, and the target optical parameter can be used as the parameter theoretical value for adjusting the actual optical structure. The target optical parameter is only a calculated value, and the transparent vibration direction of the adjustable polarization unit can be adjusted to make the current transparent vibration direction included angle the same as the target transparent vibration direction included angle. The single variable method is adopted to ensure that the optical power density of each point irradiated on the to-be-tested sample remains the same, which removes the influence of the light spot area and measures the defect information of the to-be-tested sample.

[0075] In a feasible implementation, step S500: obtaining the unit light spot area secondary harmonic wave intensity under the condition of the second incident angle and the target optical parameter, including:

[0076] The transparent vibration direction of the adjustable polarization unit is adjusted to make the second transparent vibration direction included angle the same as the target transparent vibration direction included angle.

[0077] obtaining the second-harmonic intensity per unit spot area under the second incidence angle and the target optical parameter condition.

[0078] The step of obtaining the second-harmonic intensity per unit spot area under the second incidence angle and the target optical parameter condition can comprise:

[0079] obtaining the second-harmonic intensity under the second incidence angle and the target optical parameter condition;

[0080] According to the second-harmonic intensity and the second spot area, the second-harmonic intensity per unit spot area under the second incidence angle and the target optical parameter condition L is calculated according to the following formula: S :

[0081]

[0082] wherein L is the second-harmonic intensity, and S is the second spot area.

[0083] The second-harmonic measurement method provided by the embodiments of the present application takes the second-harmonic intensity per unit spot area as the final test data, which can remove the influence of the spot area, improve the test precision, and reduce the test error.

[0084] It can be understood that after the second-harmonic measurement method provided by the embodiments of the present application is implemented, a series of calculation and analysis processes of the optical signal data of the second-harmonic intensity per unit spot area are still needed through some calculation modules or computer components with calculation and data processing capabilities, and finally the defect information or film layer property data of the sample to be tested and the corresponding parameters are obtained. For example, the corresponding parameters can be the fixed oxide charge in the dielectric layer or the interface state density, etc., which are not limited by the present application.

[0085] In a second aspect, Figure 5 The structure diagram of a second-harmonic measurement instrument provided by the embodiments of the present application is shown in FIG. 2. As shown in FIG. 2, Figure 5As shown, the embodiment of the present application provides a second harmonic measurement instrument, which comprises a laser emission assembly 100, an incident light path optical assembly 200, a detection light path optical assembly 300, a detection assembly 400 and an image acquisition assembly 500. The incident light path optical assembly 200 can be used to form the laser beam emitted by the laser emission assembly 100 into an incident laser beam to irradiate the sample A to be measured. The detection light path optical assembly 300 can be used to receive the second harmonic reflected by the sample A to be measured to the detection assembly 400. The image acquisition assembly 500 can be used to acquire the spot area irradiated on the sample A to be measured. The laser beam emitted by the laser emission assembly 100 can be incident into the incident light path optical assembly 200 through the optical fiber 600 and the coupling assembly 700 in turn, and the optical signal detected by the detection light path optical assembly can be incident into the detection assembly 400 through the coupling assembly 700 and the optical fiber 600 in turn. The coupling assembly 700 is mainly used to connect the optical assembly and the optical fiber. The sample A to be measured can be placed on the sample stage 800. The image acquisition assembly 500 can adopt an industrial camera, which can be divided into two types of CCD and CMOS, and the present application does not make specific limitation as long as it can acquire images.

[0086] With reference to the foregoing Figure 5 , the incident light path optical assembly 200 can comprise an incident optical power adjustment unit 210, which can be used to adjust the optical parameter according to the spot area to adjust the optical power of the incident laser beam irradiated on the sample A to be measured.

[0087] The second harmonic measurement instrument provided by the embodiment of the present application can adjust the optical parameter through the incident optical power adjustment unit 210, acquire the spot area through the image acquisition assembly 500, and obtain the standard optical power density according to the spot area, so that the optical power density irradiated on the sample A to be measured each time is consistent with the standard optical power density, thereby adjusting the optical parameter of the incident optical power adjustment unit 210 to obtain the unit spot area second harmonic intensity at the corresponding position of the sample A to be measured. The influence of the spot area can be removed, and the problem that when the spot area changes with the incident angle, the laser power density irradiated on the sample changes, which affects the second harmonic intensity with the defect information of the sample to be measured, and further affects the detection precision of the defect information of the sample to be measured, and reduces the test error.

[0088] In a feasible implementation manner, Figure 6 Another structure schematic diagram of the second harmonic measurement instrument provided by the embodiment of the present application is shown in FIG. 2. As shown in FIG. 2, Figure 6As shown, the incident optical power adjustment unit 210 includes a polarizing unit 211 and an adjustable polarization unit 212 arranged oppositely, and the transmission direction of the adjustable polarization unit 212 is adjustable. The optical parameter includes an included angle formed between the transmission direction of the adjustable polarization unit 212 and the transmission direction of the polarizing unit 211. The probe light path optical assembly 300 includes an analyzing unit 310.

[0089] The second harmonic measurement instrument provided by the embodiments of the present application can polarize the laser beam emitted by the laser emitting assembly 100 through the polarizing unit 211 to obtain polarized light, and polarize the reflected light through the analyzing unit 310, so as to obtain the second harmonic with a polarization state meeting the test requirements.

[0090] In a possible implementation, referring to Figure 6 The adjustable polarization unit 212 includes a polarizer 212a and a stepping motor 212b connected with the polarizer 212a. The stepping motor 212b is used to drive the polarizer 212a to rotate, so as to adjust the transmission direction of the polarizer 212a. In addition to the stepping motor 212b, other transmission assemblies, such as a rotating shaft, can also be used to drive the rotation of the polarizer 212a, which is not limited in the present application.

[0091] The second harmonic measurement instrument provided by the embodiments of the present application uses a wide range of polarizing elements as the polarizer, and the stepping motor 212b can adjust the transmission direction of the polarizer 212a.

[0092] In a possible implementation, referring to Figure 6 The image acquisition assembly 500 can be arranged between the incident light path optical assembly 200 and the probe light path optical assembly 300.

[0093] The second harmonic measurement instrument provided by the embodiments of the present application can generally realize the measurement of different points of the sample to be measured by moving the sample stage 800, or can realize the measurement of different points of the sample to be measured by moving the incident light path optical assembly 100 and the probe light path optical assembly 300, which is not limited in the present application. Regardless of the way of realizing the measurement of different points of the sample to be measured, the sample stage 800 to be measured is arranged between the incident light path optical assembly 200 and the probe light path optical assembly 300. Therefore, the image acquisition assembly 500 can be arranged between the incident light path optical assembly 200 and the probe light path optical assembly 300 and above the sample stage 800 to be measured, which can be directly above or obliquely above. The light spot area on the sample to be measured is more real, which can improve the measurement accuracy and reduce the measurement error.

[0094] In a possible implementation, referring to Figure 6The incident light path optical assembly 200 further comprises a focusing objective 220, which is arranged on the side of the incident optical power adjusting unit 210 away from the laser emitting assembly 100. The probe light path optical assembly 300 further comprises a collimating objective 320 and a filter 330, and the filter 330 is arranged between the collimating objective 320 and the probe assembly 400.

[0095] The focusing objective 220 can be used to focus the incident laser beam, the collimating objective 320 can be used to collimate the reflected light beam, and the filter 330 is mainly used to filter out the fundamental wave in the reflected light beam. Since the fundamental wave accounts for a large proportion, it needs to be filtered out, and the second harmonic wave accounting for a small proportion is retained, which carries the related defect information of the sample to be measured or the related optoelectronic parameters of the dielectric layer. This facilitates the subsequent processing of the second harmonic wave and the extraction of the defect data and the related optoelectronic parameters of the dielectric layer, improves the precision of parameter extraction, and reduces the measurement error.

[0096] It should be noted that a control device or a controller can be arranged inside or outside the second harmonic wave measuring instrument, which is used to control the opening or closing of the laser emitting assembly 100, the probe assembly 400, and the image acquisition assembly 500, control the movement of the incident light path optical assembly 200, the probe light path optical assembly 300, and the sample stage 800, such as the movement of each optical lens in the incident light path optical assembly 200 and the probe light path optical assembly 300, and can control the rotation of the polaroid 212a driven by the stepping motor 212b, and the like. A computing module or a computer component with computing and data processing capabilities can also be included to perform a series of computing and analysis processes on the optical signal data of the second harmonic wave intensity per unit spot area, which will not be described herein.

[0097] The specification is described with reference to flowcharts and / or block diagrams according to the embodiments of the specification. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices produce a device that implements the specified functions in the flowcharts and / or block diagrams. Figure 1 The device that implements the functions specified in one flow or multiple flows and / or blocks Figure 1 The device that implements the functions specified in one flow or multiple flows and / or blocks

[0098] These computer program instructions can also be loaded into a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 These computer program instructions can also be loaded into a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 These computer program instructions can also be loaded into a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

[0099] While the preferred embodiments of the application have been described, additional variations and modifications can be made to the embodiments by those skilled in the art once they learn of the basic inventive concepts. Therefore, the appended claims are intended to cover all such modifications and variations as fall within the true spirit and scope of the application.

[0100] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the application can be practiced otherwise than as specifically described herein.

Claims

1. A second harmonic measurement method, characterized by, The method comprises: acquiring a first light spot area formed by an incident laser beam at a first incident angle on a sample to be measured; acquiring a standard optical power density according to the first light spot area and a first optical parameter; acquiring a second light spot area formed by the incident laser beam at a second incident angle on the sample to be measured; acquiring a target optical parameter according to the standard optical power density and the second light spot area; acquiring a second harmonic intensity per unit light spot area under the condition of the second incident angle and the target optical parameter; the first optical parameter comprises a first transmission-vibration direction angle, which is an angle formed by a first transmission-vibration direction of an adjustable polarization unit and a transmission-vibration direction of a polarizing unit; the step of acquiring the standard optical power density according to the first light spot area and the first optical parameter comprises: acquiring the first transmission-vibration direction angle and an initial optical power of the incident laser beam; The standard optical power density is calculated according to the following formula : wherein, is the first polarization direction angle, is the initial optical power, is the first spot area; the target optical parameter comprises a target transmission-vibration direction angle, which is an angle formed by a second transmission-vibration direction of the adjustable polarization unit and the transmission-vibration direction of the polarizing unit; the step of acquiring the target optical parameter according to the standard optical power density and the second light spot area comprises: According to the standard optical power density and the second spot area, the target transmission direction angle is calculated according to the following formula : wherein, is the initial optical power of the incident laser beam, is the second spot area, is the standard optical power density.

2. The second harmonic measurement method of claim 1, wherein, the step of acquiring the second harmonic intensity per unit light spot area under the condition of the second incident angle and the target optical parameter comprises: adjusting the transmission-vibration direction of the adjustable polarization unit so that the second transmission-vibration direction angle is the same as the target transmission-vibration direction angle; acquiring the second harmonic intensity per unit light spot area under the condition of the second incident angle and the target optical parameter.

3. The second harmonic measurement method of claim 2, wherein, the step of acquiring the second harmonic intensity per unit light spot area under the condition of the second incident angle and the target optical parameter comprises: acquiring a second harmonic intensity under the condition of the second incident angle and the target optical parameter; According to the second harmonic intensity and the second spot area, the unit spot area second harmonic intensity under the condition of the second incidence angle and the target optical parameter is calculated as follows : wherein, is the second harmonic intensity, is the second spot area.

4. A second harmonic measuring instrument characterized by, The second harmonic measuring instrument applied to the second harmonic measuring method in any one of claims 1 to 3 comprises a laser emission assembly, an incident light path optical assembly, a detection light path optical assembly, a detection assembly and an image acquisition assembly; the incident light path optical assembly is used to form an incident laser beam emitted by the laser emission assembly into the incident laser beam and direct the incident laser beam to a sample to be measured; the detection light path optical assembly is used to receive a second harmonic reflected by the sample to be measured to the detection assembly; the image acquisition assembly is used to acquire a light spot area irradiated on the sample to be measured; the incident light path optical assembly comprises an incident optical power adjusting unit, which is used to adjust an optical parameter according to the light spot area to adjust an optical power of the incident laser beam irradiated on the sample to be measured.

5. The second harmonic measurement instrument of claim 4, wherein, the incident optical power adjusting unit comprises a polarizing unit and an adjustable polarization unit arranged oppositely, and a transmission-vibration direction of the adjustable polarization unit is adjustable; the optical parameter comprises an angle formed by the transmission-vibration direction of the adjustable polarization unit and a transmission-vibration direction of the polarizing unit; the detection light path optical assembly comprises a detection polarization unit.

6. The second harmonic measurement instrument of claim 5, wherein, the adjustable polarization unit comprises a polarizing sheet and a stepping motor in transmission connection with the polarizing sheet; The stepping motor is used to drive the polarizer to rotate, so as to adjust the transmission direction of the polarizer.

7. The second harmonic measurement instrument of claim 4, wherein, The image acquisition component is arranged between the incident light path optical component and the detection light path optical component.

8. The second harmonic measurement instrument of claim 4, wherein, The incident light path optical component further comprises a focusing objective lens, which is arranged on the side of the incident optical power adjusting unit away from the laser emitting component. The detection light path optical component further comprises a collimating objective lens and a filter, which is arranged between the collimating objective lens and the detection component.

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