Optical detection device and method

Abstract

The invention provides optical detection equipment and method. The optical detection equipment comprises a light source assembly for generating a light beam, a shaping lens group for shaping the light beam, and a shaping light beam for scanning the surface of a to-be-detected object; the ellipsoidal objective lens focuses a scattered light beam formed in a scattering angle range; the spectroscope divides the scattered light beam into a first light beam and a second light beam; the first detection assembly detects a first signal of the first light beam; the second detection assembly performs enhancement processing on the second light beam and detects a second signal of the enhanced second light beam; and the processing equipment is used for acquiring and analyzing the first signal detected by the first detection assembly to obtain a detection result about whether the surface of the to-be-detected object has defects or not, and acquiring and processing the second signal detected by the second detection assembly to obtain the haze of the to-be-detected object. On the basis of detecting whether the surface of the to-be-detected object has defects or not, the haze signal can be enhanced, and high-precision acquisition of the haze signal is realized.

Description

Technical Field

[0001] The present application relates to the field of defect detection technology, and in particular to an optical detection device and method. Background Art

[0002] The image-free wafer defect detection electronic equipment detects defects on bare wafers, film layer wafers and other types of high-precision wafers. The detection accuracy of this detection process is at the nanometer level. The accuracy and stability of the wafer defect detection electronic equipment are important guarantees for chip production yield. The image-free wafer defect detection electronic equipment has different accuracy detection requirements for different chip processing technologies. At present, the highest process accuracy of chips in the semiconductor field has reached 30nm, but the wafer defect detection electronic equipment with this process accuracy has extremely high costs and low detection efficiency. In the field of industrial-grade chip detection, the process accuracy of chips is relatively low, and there are higher requirements for the cost and detection efficiency of wafer defect detection electronic equipment.

[0003] In the related art, wafer defect detection enhances or attenuates defect detection signals and haze signals by adding polarization filters and apertures of different shapes to the focusing transmission system, thereby improving the signal-to-noise ratio of defects and the detection accuracy of haze signals. Among them, the signal enhancement aperture is designed to improve the detection accuracy of particle size, and the enhanced detection scheme of particle signals is only for imageless wafer defect detection electronic equipment with a lens group as an objective lens. Specifically, it improves the particle detection signal-to-noise ratio by reducing the haze signal, but the haze signal is an important parameter reflecting the roughness of the wafer. Excessive filtering of the wafer haze signal will lead to an increase in the wafer haze measurement error, resulting in a decrease in the roughness detection accuracy. In the field of detection of defects at the order of 30 nanometers, the signal-to-noise ratio of the particle signal is high within the detection capability range, but the haze level is limited by the stray light of the ellipsoidal mirror, and the detection accuracy is limited. It is impossible to effectively obtain the haze signal under the premise of ensuring the particle detection accuracy. Summary of the invention

[0004] The present application provides an optical detection device and method to at least solve the above technical problems existing in the prior art.

[0005] According to a first aspect of the present application, an optical detection device is provided, comprising:

[0006] A light source assembly, for generating a light beam;

[0007] A shaping lens assembly, used for shaping the light beam to obtain a shaped light beam;

[0008] A turntable, used for placing the object to be measured and driving the object to be measured to rotate, so as to enable the shaped light beam to scan the surface of the object to be measured;

[0009] An ellipsoidal objective lens, used for focusing a scattered light beam formed within a scattering angle range after the shaped light beam scans the surface of the object to be measured;

[0010] A beam splitter, used for splitting the scattered light beam into a first light beam and a second light beam;

[0011] A first detection component, used for detecting a first signal of the first light beam;

[0012] A second detection component, used for enhancing the second light beam and detecting a second signal of the enhanced second light beam;

[0013] The processing device is used to obtain the first signal detected by the first detection component and analyze it to obtain the detection result of whether there are defects on the surface of the object to be tested, and to obtain the second signal detected by the second detection component and process it to obtain the haze of the object to be tested.

[0014] In one embodiment, the shaping lens assembly comprises:

[0015] A shaping mirror, used for shaping the light beam generated by the light source assembly to obtain an initial shaped light beam;

[0016] The adjusting mirror is used to achieve stable pointing of the initial shaped light beam to obtain the shaped light beam.

[0017] In one possible implementation, the first detection assembly includes: a first transmission mirror set and a first detector;

[0018] The ellipsoid objective lens, the beam splitter, the first transmission lens group and the first detector are arranged in sequence from bottom to top;

[0019] The first transmission mirror assembly is used to transmit the first light beam to the first detector;

[0020] The first detector is used to detect a first signal of the first light beam.

[0021] In one possible implementation, the first detection assembly further includes: a first polarizer and a first aperture;

[0022] The first transmission mirror group, the first polarizer, the first aperture and the first detector are arranged in sequence from bottom to top;

[0023] The first polarizer is used to select a first target polarization state for the first light beam;

[0024] The first aperture is used to select a first target scattered light distribution area for the first light beam after polarization state selection;

[0025] Wherein, the first polarizer and the first aperture are installed on the image plane of the first transmission lens assembly.

[0026] In one possible implementation, the second detection assembly includes: a second transmission mirror set and a second detector;

[0027] The beam splitter, the second transmission mirror set and the second detector are arranged in sequence from left to right;

[0028] The second transmission mirror assembly is used to transmit the second light beam to the second detector;

[0029] The second detector is used for detecting a second signal of the second light beam.

[0030] In one possible implementation, the second detection assembly further includes: a second polarizer and a second aperture;

[0031] The beam splitter, the second transmission lens group, the second polarizer, the second aperture and the second detector are arranged in sequence from left to right;

[0032] The second polarizer is used to select a second target polarization state for the second light beam;

[0033] The second aperture is used to select a second target scattered light distribution area for the second light beam after polarization state selection.

[0034] In one possible implementation manner, the first detector and / or the second detector is / are a multi-channel detector, a single-channel detector or a time-delayed integration linear array camera.

[0035] In one possible implementation manner, the scattering angle ranges from 0° to 75°.

[0036] In one possible implementation manner, the light beam generated by the light source assembly is a continuous wave narrow line width single-biased light beam in the ultraviolet band.

[0037] In one possible implementation manner, a vacuum adsorption hole is provided on the surface of the turntable for vacuum adsorption of the object to be measured.

[0038] According to a second aspect of the present application, an optical detection method is provided, the method comprising:

[0039] Place the object to be tested on the turntable;

[0040] Turning on the light source assembly to generate a light beam, the light beam is shaped by the shaping lens group to obtain a shaped light beam, the turntable is operated to make the shaped light beam scan the entire surface of the object to be measured to form a scattered light beam, and the ellipsoidal objective lens is used to focus the scattered light beam formed within the scattering angle range;

[0041] Splitting the scattered light beam into a first light beam and a second light beam by a beam splitter;

[0042] Using a first detection component to detect a first signal of the first light beam, and using a second detection component to enhance the second light beam and detect a second signal of the enhanced second light beam;

[0043] The first signal is analyzed to determine whether there are defects on the surface of the object to be measured, and the second signal is analyzed to obtain the haze of the object to be measured.

[0044] In one possible implementation manner, the light beam is shaped by a shaping lens group to obtain a shaped light beam, comprising:

[0045] Shaping the light beam generated by the light source assembly by a shaping mirror to obtain an initial shaped light beam;

[0046] The initial shaped light beam is pointed stably by adjusting the mirror to obtain a shaped light beam.

[0047] In one embodiment, before using the first detection component to detect the first signal of the first light beam, the method further includes:

[0048] Selecting the polarization state of the first light beam by using a first polarizer;

[0049] The first aperture is used to select the distribution area of ​​the scattered light in the plane of the first light beam after the polarization state is selected.

[0050] In one possible implementation manner, the step of performing enhancement processing on the second light beam by using the second detection component includes:

[0051] Selecting the polarization state of the second light beam by using a second polarizer;

[0052] The second light beam after polarization state selection is performed using the second aperture to select the scattered light distribution area of ​​the image plane.

[0053] In one possible implementation manner, analyzing the second signal to obtain the haze of the object to be measured includes:

[0054] Based on the second signal, a haze extraction algorithm is used to obtain a haze average value of the object to be measured.

[0055] In one embodiment, before turning on the light source assembly to generate the light beam, the method further includes:

[0056] Obtaining roughness data of the surface of the object to be measured;

[0057] Determining the scattering field of the object to be measured using a scattering field model based on the roughness data;

[0058] Determining a second target polarization state and a second target scattered light distribution area according to the scattering field of the object to be measured;

[0059] A second polarizer is selected according to the second target polarization state, and a second aperture is selected according to the second target scattered light distribution area.

[0060] In one possible implementation manner, after obtaining the haze of the object to be measured, the method further includes:

[0061] The obtained haze is compared with the haze obtained by other detection electronic equipment to obtain the haze detection accuracy;

[0062] Replace the second polarizer and the second aperture to obtain a new haze, and iteratively optimize until a target haze accuracy is obtained;

[0063] The target haze accuracy is better than all calculated haze detection accuracies.

[0064] In one possible implementation manner, the obtained haze is compared with the haze obtained by other detection electronic devices to obtain the haze detection accuracy, including:

[0065] Acquire a plurality of objects to be measured with different haze accuracy levels to obtain a plurality of haze measurement results;

[0066] The multiple haze measurement results are compared with the haze obtained by corresponding other detection electronic devices, and the haze detection accuracy is calculated based on the comparison results.

[0067] In one possible implementation manner, after the iterative optimization is performed to obtain the target haze accuracy, the method further comprises:

[0068] When the target haze accuracy is obtained, the polarizer parameters of the second polarizer and the aperture shape parameters of the second aperture are determined.

[0069] According to a third aspect of the present application, an electronic device is provided, including:

[0070] at least one processor; and

[0071] a memory communicatively connected to the at least one processor; wherein,

[0072] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method described in the present application.

[0073] According to a fourth aspect of the present application, a non-transitory computer-readable storage medium storing computer instructions is provided, wherein the computer instructions are used to enable the computer to execute the method described in the present application.

[0074] The optical detection equipment and method of the present application are as follows: the shaping mirror of the present application shapes the light beam generated by the light source component, and then the shaped light beam irradiates the surface of the object to be measured to generate a scattered light beam, the ellipsoidal objective lens focuses the scattered light beam to shine it on the beam splitter, the beam splitter divides the scattered light beam into a first light beam and a second light beam, the first light beam enters the first detection component, and the second light beam enters the second detection component, the processing device analyzes the first signal of the first light beam to obtain the detection result of whether there are defects on the surface of the object to be measured, and the processing device enhances and analyzes the second signal of the second light beam to obtain the haze of the object to be measured; the technical solution of the present application adds a beam splitter to the defect detection equipment, and at the same time realizes the surface defects of the crystal material and the high-precision acquisition of the haze signal, which makes up for the problem that the particle measurement accuracy and the haze measurement accuracy cannot be enhanced at the same time, and the haze detection accuracy is limited.

[0075] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present application, nor is it intended to limit the scope of the present application. Other features of the present application will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present application will become readily understood. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-limiting manner, wherein:

[0077] In the drawings, the same or corresponding reference numerals represent the same or corresponding parts.

[0078] Figure 1 A schematic diagram of the structure of an optical detection device according to an embodiment of the present application is shown;

[0079] Figure 2 A schematic diagram of the process of the optical detection method according to an embodiment of the present application is shown;

[0080] Figure 3 The haze scattering field distribution diagram of a micro-rough wafer surface under normal incidence in an embodiment of the present application is shown;

[0081] Figure 4 The haze scattering field distribution diagram of a micro-rough wafer surface under oblique incidence in an embodiment of the present application is shown;

[0082] Figure 5 The image plane scattering field distribution diagram when a wafer with a certain roughness contains particle defects in an embodiment of the present application is shown;

[0083] Figure 6 A schematic diagram of the structure of an electronic device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0084] In order to make the purpose, features, and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0085] The signal enhancement aperture design in the prior art is to improve the detection accuracy of particle size. The existing enhanced detection scheme for particle signals is for imageless wafer defect detection equipment using a lens group as an objective lens. Therefore, the prior art does not yet have a signal enhancement detection method for imageless wafer detection equipment based on an ellipsoidal lens objective solution, nor does it have an enhanced detection method for haze signals. The existing defect detection scheme improves the particle detection signal-to-noise ratio by reducing the haze signal, but the haze signal is an important parameter that reflects the roughness of the wafer. Excessive filtering of the wafer haze signal will lead to an increase in the wafer haze measurement error and a decrease in the roughness detection accuracy. In the field of detection of defects of the order of 30nm, the signal-to-noise ratio of the particle signal is relatively high within the detection capability range, but the haze level is limited by the stray light of the ellipsoidal mirror and the detection accuracy is limited. Therefore, it is necessary to effectively obtain the haze signal while ensuring the particle detection accuracy.

[0086] An optical detection device and method provided by the present application are introduced below in conjunction with the accompanying drawings.

[0087] like Figure 1 As shown, the present application provides an optical detection device, the device comprising:

[0088] A light source assembly 1, for generating a light beam;

[0089] A shaping lens group 2, used for shaping the light beam to obtain a shaped light beam;

[0090] The turntable 3 is used to place the object to be measured 4 and drive the object to be measured 4 to rotate, so as to realize the scanning of the surface of the object to be measured 4 by the shaped light beam;

[0091] An ellipsoidal objective lens 5 is used to focus a scattered light beam formed within a scattering angle range after the shaped light beam scans the surface of the object to be measured 4;

[0092] A beam splitter 6, used for splitting the scattered light beam into a first light beam and a second light beam;

[0093] A first detection component 7, used for detecting a first signal of the first light beam;

[0094] A second detection component 8, used for enhancing the second light beam and detecting a second signal of the enhanced second light beam;

[0095] A processing device (not shown in the figure) is used to obtain and analyze the first signal detected by the first detection component 7 to obtain a detection result of whether there are defects on the surface of the object to be tested 4, and to obtain and process the second signal detected by the second detection component 8 to obtain the haze of the object to be tested 4.

[0096] Wherein, the object to be measured 4 in the present application can be a wafer, and the light source assembly 1 in the present application can be a laser generator, and the laser generator can generate a laser light source, and the laser light source is a single polarization light source with a continuous wave narrow line width in the ultraviolet band, and the light source has high pointing stability. Wherein, the polarization state of the light emitted by the light source is single polarization, and can be selected between S polarization and P polarization. In the present application, P polarization light is preferably incident. The shaping lens group 2 can shape the light beam generated by the light source assembly 1 into a specific shape to obtain a shaped light beam, and the shaped light beam irradiates the object to be measured 4, and the object to be measured 4 is arranged on a turntable 3, and the turntable 3 can drive the object to be measured 4 to rotate, so that the shaped light beam can irradiate the entire surface of the object to be measured 4, and generate a scattered light beam, and the ellipsoidal objective lens 5 focuses the scattered light beam, and the focused scattered light beam irradiates the beam splitter 6, and the beam splitter 6 divides the focused scattered light beam into a first light beam and a second light beam, wherein the first light beam enters the first detection assembly 7, and the second light beam enters the second detection assembly 8, and the first detection assembly 7 sends the first signal of the detected first light beam to the processing device, and the processing device can analyze whether there is a defect on the surface of the object to be measured 4 according to the first signal. The second detection component 8 can enhance the second signal of the second light beam, and send the enhanced second signal to the processing device, which analyzes the second signal to obtain the haze of the object to be measured 4. It can be understood that the processing device in the present application can be a device with analysis and processing capabilities such as a computer.

[0097] Among them, the surface of the turntable 3 in the present application is provided with a vacuum adsorption hole for vacuum adsorption of the object to be measured 4. The turntable 3 can vacuum adsorb the wafer to complete the high-speed rotation of the wafer, and realize the scanning of the entire surface of the wafer by cooperating with the translation of the turntable 3. The ellipsoidal collection objective lens can collect and transmit the scattering field in the scattering angle range of 0° to 75° on the wafer surface.

[0098] The optical detection device provided in the present application adds a spectroscope 6 to the defect detection device, which can realize high-precision acquisition of haze signals while detecting surface defects of crystal materials, thereby compensating for the problem that the particle measurement accuracy and haze measurement accuracy cannot be enhanced at the same time and the haze detection accuracy is limited.

[0099] In some embodiments, the shaping lens assembly 2 comprises:

[0100] A shaping mirror 201, used for shaping the light beam generated by the light source assembly 1 to obtain an initial shaped light beam;

[0101] The adjusting mirror 202 is used to achieve stable pointing of the initial shaped light beam to obtain a shaped light beam.

[0102] It can be understood that the shaping mirror group 2 in the present application includes a shaping mirror 201 that shapes the light spot of the light source into a specific shape and an adjustment mirror 202 that realizes stable and adjustable pointing of the light source; the optical detection equipment provided by the present application can also include an illumination system (not shown in the figure), and the illumination system cooperates with the collimating shaping mirror group 2 to achieve a large angle of incidence on the surface of the object to be measured 4, so as to improve the imaging contrast of dark field illumination.

[0103] In some embodiments, the first detection assembly 7 includes: a first transmission mirror assembly 701 and a first detector 704;

[0104] The ellipsoid objective lens 5, the beam splitter 6, the first transmission lens group 701 and the first detector 704 are arranged in sequence from bottom to top;

[0105] The first transmission mirror assembly 701 is used to transmit the first light beam to the first detector 704;

[0106] The first detector 704 is used to detect the first signal of the first light beam.

[0107] Specifically, the first light beam is transmitted to the first detector 704 through the first transmission mirror group 701, and the first detector 704 detects the first signal of the first light beam.

[0108] In some embodiments, the first detection assembly 7 further includes: a first polarizer 702 and a first aperture 703;

[0109] The first transmission lens group 701, the first polarizer 702, the first aperture 703 and the first detector 704 are arranged in sequence from bottom to top;

[0110] The first polarizer 702 is used to select a first target polarization state for the first light beam;

[0111] The first aperture 703 is used to select a first target scattered light distribution area for the first light beam after polarization state selection;

[0112] The first polarizer 702 and the first aperture 703 are installed on the image plane of the first transmission lens group 701 .

[0113] In the present application, the first light beam is transmitted to the first polarizer 702 through the first transmission lens group 701. The first polarizer 702 selects the first target polarization state of the first light beam. Then the first aperture 703 selects the first target scattered light distribution area for the first light beam after the polarization state selection. The selected first light beam enters the first detector 704.

[0114] The first polarizer 702 and the first aperture 703 are installed on the image plane of the first transmission lens group 701 because the image plane of the first transmission lens group 701 can filter out the spatial region and polarization state of the target.

[0115] In some embodiments, the second detection assembly 8 includes: a second transmission mirror assembly 801 and a second detector 804;

[0116] The beam splitter 6, the second transmission mirror set 801 and the second detector 804 are arranged in sequence from left to right;

[0117] The second transmission mirror group 801 is used to transmit the second light beam to the second detector 804;

[0118] The second detector 804 is used to detect the second signal of the second light beam.

[0119] Specifically, the second light beam is transmitted to the first detector 704 through the second transmission mirror group 801, and the second detector 804 detects the second signal of the second light beam.

[0120] In some embodiments, the second detection assembly 8 further includes: a second polarizer 802 and a second aperture 803;

[0121] The beam splitter 6, the second transmission lens group 801, the second polarizer 802, the second aperture 803 and the second detector 804 are arranged in sequence from left to right;

[0122] The second polarizer 802 is used to select a second target polarization state for the second light beam;

[0123] The second aperture 803 is used to select a second target scattered light distribution area for the second light beam after polarization state selection.

[0124] In the present application, the second light beam is transmitted to the second polarizer 802 through the second transmission lens group 801, the second polarizer 802 selects the second target polarization state of the second light beam, and then the second aperture 803 selects the second target scattered light distribution area for the second light beam after polarization state selection, and the selected second light beam enters the first detector 704.

[0125] The first detector 704 and the second detector 804 can be of the same model or different models, and can be replaced by a multi-channel, single-channel, time-delayed integrated linear array camera or other ultraviolet-band sensitive weak energy detector. It should be understood that the first polarizer 702 and the first aperture 703 are installed on the image plane of the ellipsoidal objective 5 and the first transmission lens group 701. The second polarizer 802 and the second aperture 803 are installed on the image plane of the ellipsoidal objective 5 and the second transmission lens group 801.

[0126] As a specific embodiment, the light source component 1 is controlled to be turned on to generate a continuous wave narrow linewidth single polarization light source in the ultraviolet band. The light beam is irradiated to the shaping lens group 2, and the light source spot is shaped into a specific morphology through the shaping lens 201. Then, the light source pointing is made stable and adjustable through the adjusting mirror 202. Then, the shaped light beam irradiates the surface of the wafer. Under the rotation of the turntable 3, the full surface of the wafer is scanned in coordination with the translation of the turntable 3 to form a scattered light beam. The scattered light beam passes through the ellipsoidal objective lens 5, and the ellipsoidal objective lens 5 can focus the scattered light beam. The focused scattered light beam passes through the beam splitter 6 to form a first light beam and a second light beam. The first light beam is transmitted to the first polarizer 702 through the first transmission lens group 701 for polarization state selection, and then passes through the first aperture 703 to select the first target scattered light distribution area, and enters the first detector 704. The first detector 704 detects the first signal of the first light beam to achieve the highest particle detection sensitivity, and then the first signal is analyzed by the processing equipment to determine whether there is a defect on the wafer surface. The second light beam is transmitted to the second polarizer 802 through the second transmission mirror group 801 for polarization state selection, and then passes through the second aperture 803 to select the second target scattered light distribution area, and enters the second detector 804. The second detector 804 detects the second signal of the second light beam to achieve the highest haze detection accuracy, and then the second signal is analyzed by the processing equipment to determine the haze of the wafer.

[0127] like Figure 2 As shown, an embodiment of the present application provides an optical detection method, the method comprising:

[0128] S201, placing the object 4 to be tested on the turntable 3;

[0129] S202, turning on the light source assembly 1 to generate a light beam, the light beam is shaped by the shaping lens group 2 to obtain a shaped light beam, the turntable 3 is operated to make the shaped light beam scan the entire surface of the object to be measured 4 to form a scattered light beam, and the ellipsoidal objective lens 5 is used to focus the scattered light beam formed within the scattering angle range;

[0130] S203, splitting the scattered light beam into a first light beam and a second light beam by a beam splitter 6;

[0131] S204, using the first detection component 7 to detect the first signal of the first light beam, and using the second detection component 8 to enhance the second light beam, and detecting the second signal of the enhanced second light beam;

[0132] S205 , analyzing the first signal to determine whether there are defects on the surface of the object to be tested 4 , and analyzing the second signal to obtain the haze of the object to be tested 4 .

[0133] The optical detection method provided by the present application firstly uses vacuum adsorption to adsorb the wafer on the turntable 3, then turns on the light source assembly 1 to generate a light beam, and after the light beam is shaped by the shaping lens group 2, it irradiates the surface of the wafer to form a scattered light beam, and the scattered light beam is focused by the ellipsoid objective lens 5 and irradiated to the beam splitter 6 to form a first light beam and a second light beam, wherein the first light beam enters the first detection assembly 7, and the second light beam enters the second detection assembly 8. The first signal detected by the first detection assembly 7 can be analyzed to determine whether there is a defect on the wafer surface, and the second signal of the second detector 804 can be analyzed to obtain the haze of the object to be measured 4. Among them, the second detection assembly 8 can also enhance the second light beam to improve the detection level of haze.

[0134] In some embodiments, the light beam is shaped by the shaping lens group 2 to obtain a shaped light beam, including:

[0135] The light beam generated by the light source assembly 1 is shaped by a shaping mirror 201 to obtain an initial shaped light beam;

[0136] The initial shaped light beam is pointed stably by adjusting the mirror 202 to obtain a shaped light beam.

[0137] In some embodiments, before using the first detection component 7 to detect the first signal of the first light beam, the method further includes:

[0138] Selecting the polarization state of the first light beam by using the first polarizer 702;

[0139] The first aperture 703 is used to select the plane scattered light distribution area of ​​the first light beam after polarization state selection.

[0140] It is understandable that in the present application, the polarization state and scattered light distribution area of ​​the light beam can be selected according to the needs. For example, if it is necessary to detect defects on the surface of the wafer, the first target polarization state and the first target scattered light distribution area of ​​the first light beam are required. The polarizer parameters and the aperture parameters are determined according to the first target polarization state and the first target scattered light distribution area, thereby determining the first polarizer 702 and the first aperture 703. It should be noted that in the optical detection method provided in the present application, a single-wavelength single-polarization laser with an extremely narrow linewidth is used. The scattered light of different polarization states and spatial regions is selected by the first polarizer 702 and the first aperture 703. The scattered light of this polarization state in this region contains more obvious defect information. Thereby, the first signal of the first light beam obtained by the first detector 704 can be analyzed to obtain the detection result of whether there are defects on the wafer surface.

[0141] In some embodiments, the step of performing enhancement processing on the second light beam by using the second detection component 8 includes:

[0142] Selecting the polarization state of the second light beam by using the second polarizer 802;

[0143] The second aperture 803 is used to select the scattered light distribution area of ​​the image plane for the second light beam after the polarization state selection.

[0144] Similarly, when the haze of the wafer needs to be calculated, the second target polarization state and the second target scattered light distribution area of ​​the second light beam are required, and the polarizer parameters and the aperture parameters are determined according to the second target polarization state and the second target scattered light distribution area, thereby determining the second polarizer 802 and the second aperture 803. The required signal is then input into the processing device for analysis to obtain the haze of the wafer.

[0145] In some embodiments, analyzing the second signal to obtain the haze of the object to be measured 4 includes:

[0146] Based on the second signal, a haze extraction algorithm is used to obtain the average haze value of the object to be measured 4.

[0147] Specifically, in the present application, the second signal received by the second detector 804 is used to obtain the average haze value of the wafer based on the haze extraction algorithm.

[0148] In some embodiments, before turning on the light source assembly 1 to generate a light beam, the process further includes:

[0149] Obtaining roughness data of the surface of the object to be measured 4;

[0150] Determine the scattering field of the object 4 to be measured using a scattering field model based on the roughness data;

[0151] Determine a second target polarization state and a second target scattered light distribution area according to the scattering field of the object to be measured 4;

[0152] The second polarizer 802 is selected according to the second target polarization state, and the second aperture 803 is selected according to the second target scattered light distribution area.

[0153] If the present application wants to use an optical detection device to obtain the wafer haze, it is necessary to obtain the roughness data of the wafer surface before starting the optical detection device. It should be noted that in the characterization method of wafer roughness, the isotropic surface properties of the wafer can be characterized by the power spectral density function method of the ABC parameters. After polishing of different types of wafers is completed, the initial roughness data will be output.

[0154] Then the roughness data is input into the scattering field model. It should be noted that the scattering field model can simulate the scattering field of the wafer surface with different substrate materials, roughness levels, incident angles, incident wavelengths, scattering angle collection ranges, incident polarization states, and outgoing polarization states based on the bidirectional reflectance distribution function (BRDF) principle of the micro-rough surface. For example, when the P-polarized light emitted by the light source is incident on a wafer surface, Figure 3 The distribution characteristics of P polarized light in the scattering angle range of 0 to 90° of the wafer surface scattering field simulated by the scattering field model. After determining the scattering field of the object to be measured 4, the required second target polarization state and the second target scattered light distribution area can be determined; thus, the corresponding second polarizer 802 and second aperture 803 can be selected.

[0155] It can be understood that the polarizer parameters can be determined according to the second target polarization state, and the aperture parameters can be determined according to the second target scattered light distribution area, so as to select the polarizer corresponding to the polarizer parameters and the aperture corresponding to the aperture parameters. The determined second polarizer 802 and second aperture 803 are placed in front of the second detector 804.

[0156] In some embodiments, after obtaining the haze of the object to be measured 4, the method further includes:

[0157] The obtained haze is compared with the haze obtained by other detection electronic equipment to obtain the haze detection accuracy;

[0158] Replace the second polarizer 802 and the second aperture 803 to obtain a new haze, and iteratively optimize until the target haze accuracy is obtained;

[0159] The target haze accuracy is better than all calculated haze detection accuracies.

[0160] It should be noted that after calculating the haze of the wafer, the haze result can also be compared with the haze detected by other high-precision detection equipment to verify the accuracy of the haze obtained by the optical detection device provided in this application. The new haze of the wafer is obtained by replacing the second polarizer 802 and the second aperture 803. After iterative optimization, when the target haze accuracy is obtained, the optimal haze polarizer parameters and aperture aperture shape of the wafer are obtained. It should be noted that the target haze accuracy is higher than all the haze detection accuracies obtained.

[0161] In some embodiments, the obtained haze is compared with the haze obtained by other detection electronic devices to obtain the haze detection accuracy, including:

[0162] Acquire a plurality of objects 4 to be measured with different haze accuracy levels, and obtain a plurality of haze measurement results;

[0163] The multiple haze measurement results are compared with the haze obtained by corresponding other detection electronic devices, and the haze detection accuracy is calculated based on the comparison results.

[0164] Specifically, by testing a group of four wafers with different haze accuracy levels (different polishing levels), a group of haze measurement results are generated, and compared with the results measured by a higher-precision roughness measurement device, the haze enhancement measurement accuracy at this time is obtained. The haze value of the wafer can be different gradients, and the PPM value unit of the same equipment can be: 100ppm, 10ppm, 1ppm, 0.1ppm.

[0165] In some embodiments, after the iterative optimization is performed to obtain the target haze accuracy, the method further includes:

[0166] When the target haze accuracy is obtained, the polarizer parameters of the second polarizer 802 and the aperture shape parameters of the second aperture 803 are determined.

[0167] It can be understood that the corresponding polarizer and aperture can be determined according to the polarizer parameters and the aperture clear aperture shape parameters, so that the haze of the wafer can be obtained more accurately.

[0168] The optical detection method provided by the present application can not only ensure the highest accuracy of particle detection, but also ensure the highest accuracy of haze detection level. While meeting the particle size accuracy requirements, the haze is enhanced to ensure the accuracy level of the haze. It makes up for the problem that the particle measurement accuracy and the haze measurement accuracy cannot be enhanced at the same time, and the haze measurement level is improved. In addition, the optical detection method provided by the present application can adapt to wafers with different polishing accuracies and different film layers. The design of the haze polarizer and aperture can be quickly migrated and applied to wafers with different roughness levels and different film layers, and has strong adaptability. It makes up for the problem of limited haze detection accuracy of defect detection equipment.

[0169] An embodiment of the present application provides an electronic device, including:

[0170] at least one processor; and

[0171] a memory communicatively connected to the at least one processor; wherein,

[0172] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method described in any one of the above embodiments.

[0173] An embodiment of the present application provides a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to enable a computer to execute the method described in any of the above embodiments.

[0174] According to an embodiment of the present application, the present application also provides an electronic device and a readable storage medium.

[0175] Figure 6 A schematic block diagram of an example electronic device 800 that can be used to implement an embodiment of the present application is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable electronic devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present application described and / or required herein.

[0176] like Figure 6 As shown, the electronic device 800 includes a computing unit 801, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 802 or a computer program loaded from a storage unit 808 into a random access memory (RAM) 803. In the RAM 803, various programs and data required for the operation of the electronic device 800 can also be stored. The computing unit 801, the ROM 802, and the RAM 803 are connected to each other via a bus 804. An input / output (I / O) interface 805 is also connected to the bus 804.

[0177] A number of components in the electronic device 800 are connected to the I / O interface 805, including: an input unit 806, such as a keyboard, a mouse, etc.; an output unit 807, such as various types of displays, speakers, etc.; a storage unit 808, such as a disk, an optical disk, etc.; and a communication unit 809, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 809 allows the electronic device 800 to exchange information / data with other electronic devices through a computer network such as the Internet and / or various telecommunication networks.

[0178] The computing unit 801 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 801 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 801 performs the various methods and processes described above, such as the optical detection method. For example, in some embodiments, the optical detection method may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit 808. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 800 via the ROM 802 and / or the communication unit 809. When the computer program is loaded into the RAM 803 and executed by the computing unit 801, one or more steps of the optical detection method described above may be performed. Alternatively, in other embodiments, the computing unit 801 may be configured to perform the optical detection method in any other appropriate manner (e.g., by means of firmware).

[0179] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0180] The program code for implementing the method of the present application can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the program code, when executed by the processor or controller, implements the functions / operations specified in the flow chart and / or block diagram. The program code can be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0181] In the context of the present application, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or electronic device. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or electronic device, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage electronic device, a magnetic storage electronic device, or any suitable combination of the foregoing.

[0182] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0183] The systems and techniques described herein may be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), and the Internet.

[0184] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship of client and server is generated by computer programs running on respective computers and having a client-server relationship with each other. The server may be a cloud server, a server of a distributed system, or a server combined with a blockchain.

[0185] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in this application can be achieved, and this document is not limited here.

[0186] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0187] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An optical detection device, characterized in that: The device comprises: A light source assembly, for generating a light beam; A shaping lens assembly, used for shaping the light beam to obtain a shaped light beam; A turntable, used for placing the object to be measured and driving the object to be measured to rotate, so as to enable the shaped light beam to scan the surface of the object to be measured; An ellipsoidal objective lens, used for focusing a scattered light beam formed within a scattering angle range after the shaped light beam scans the surface of the object to be measured; A beam splitter, used for splitting the scattered light beam into a first light beam and a second light beam; A first detection component, used for detecting a first signal of the first light beam; A second detection component, used for enhancing the second light beam and detecting a second signal of the enhanced second light beam; The processing device is used to obtain the first signal detected by the first detection component and analyze it to obtain the detection result of whether there are defects on the surface of the object to be tested, and to obtain the second signal detected by the second detection component and process it to obtain the haze of the object to be tested.

2. The device according to claim 1, characterized in that The plastic surgery lens set comprises: A shaping mirror, used for shaping the light beam generated by the light source assembly to obtain an initial shaped light beam; The adjusting mirror is used to achieve stable pointing of the initial shaped light beam to obtain the shaped light beam.

3. The device according to claim 1, characterized in that The first detection assembly comprises: a first transmission mirror assembly and a first detector; The ellipsoid objective lens, the beam splitter, the first transmission lens group and the first detector are arranged in sequence from bottom to top; The first transmission mirror assembly is used to transmit the first light beam to the first detector; The first detector is used to detect a first signal of the first light beam.

4. The device according to claim 3, characterized in that The first detection assembly further includes: a first polarizer and a first aperture; The first transmission mirror group, the first polarizer, the first aperture and the first detector are arranged in sequence from bottom to top; The first polarizer is used to select a first target polarization state for the first light beam; The first aperture is used to select a first target scattered light distribution area for the first light beam after polarization state selection; Wherein, the first polarizer and the first aperture are installed on the image plane of the first transmission lens assembly.

5. The device according to claim 3, characterized in that The second detection assembly includes: a second transmission mirror group and a second detector; The beam splitter, the second transmission mirror set and the second detector are arranged in sequence from left to right; The second transmission mirror assembly is used to transmit the second light beam to the second detector; The second detector is used for detecting a second signal of the second light beam.

6. The device according to claim 5, characterized in that The second detection assembly further includes: a second polarizer and a second aperture; The beam splitter, the second transmission lens group, the second polarizer, the second aperture and the second detector are arranged in sequence from left to right; The second polarizer is used to select a second target polarization state for the second light beam; The second aperture is used to select a second target scattered light distribution area for the second light beam after polarization state selection.

7. The device according to claim 5, characterized in that The first detector and / or the second detector is a multi-channel detector, a single-channel detector or a time-delayed integrated linear array camera.

8. An optical detection method, characterized in that: The method comprises: Place the object to be tested on the turntable; Turning on the light source assembly to generate a light beam, the light beam is shaped by the shaping lens group to obtain a shaped light beam, the turntable is operated to make the shaped light beam scan the entire surface of the object to be measured to form a scattered light beam, and the ellipsoidal objective lens is used to focus the scattered light beam formed within the scattering angle range; Splitting the scattered light beam into a first light beam and a second light beam by a beam splitter; Using a first detection component to detect a first signal of the first light beam, and using a second detection component to enhance the second light beam and detect a second signal of the enhanced second light beam; The first signal is analyzed to determine whether there are defects on the surface of the object to be measured, and the second signal is analyzed to obtain the haze of the object to be measured.

9. An electronic device, characterized in that: include: at least one processor; as well as a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium storing computer instructions, characterized in that: The computer instructions are used to make a computer execute the method according to any one of claims 1-7.

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