Semiconductor defect detection apparatus, semiconductor defect detection method

Abstract

This application provides a semiconductor defect detection device and a semiconductor defect detection method. The semiconductor defect detection device includes a first light source, a schlieren microscope assembly, a schlieren imaging component, and a differential interference microscope assembly. This application utilizes a lens assembly to refract the density difference formed at the defect of the test object, and uses a knife-edge assembly to block irrelevant light flux, thereby enhancing the light refracted due to the density difference at the defect of the test object, accurately capturing the changes in light signal caused by the defect, and then uses the schlieren imaging component to form a schlieren image to locate the defect of the test object, and uses the differential interference microscope assembly to acquire a fine image of the defect to complete the defect detection of the test object, realizing non-destructive and rapid semiconductor defect detection, which not only improves the detection efficiency and accuracy of semiconductor defect detection, but also avoids damage to the test object.

Description

Technical Field

[0001] This application belongs to the field of semiconductor defect detection technology, specifically relating to semiconductor defect detection equipment and semiconductor defect detection methods. Background Technology

[0002] In related technologies, semiconductor defect detection mainly relies on three types of detection methods: bright / dark field optical detection, electron beam detection, and manual visual inspection. However, all of these methods have significant shortcomings: bright / dark field detection has insufficient penetration and a low rate of specific defect identification; electron beam detection is slow and destructive; and manual visual inspection is inefficient and has a high rate of missed detection. Summary of the Invention

[0003] In view of this, the first aspect of this application provides a semiconductor defect detection device, the semiconductor defect detection device comprising: The first light source is used to emit the detection beam; A schlieren microscope assembly includes a lens assembly and a blade assembly. The lens assembly has an observation area for accommodating an object to be tested. A detection beam is incident on the lens assembly and the object to be tested to form a first beam. The blade assembly receives the first beam and also blocks a portion of the light flux of the first beam while allowing a second beam to pass through. The second beam is refracted by the object to be tested. A schlieren imaging component for receiving the second beam and forming a schlieren image; The differential interference microscope array is used to acquire fine images of the defects in the object under test.

[0004] The lens assembly includes: A first schlieren lens is disposed on one side of the first light source, and the first schlieren lens is used to collimate the detection beam. A second schlieren lens is disposed between the first schlieren lens and the blade assembly. The observation area is located between the first schlieren lens and the second schlieren lens. The second schlieren lens is used to focus the detection beam and form the first beam.

[0005] The semiconductor defect detection device further includes a processor, which is electrically connected to the schlieren imaging component and the differential interference microscope group. The processor is used to acquire first image information of the schlieren image and second image information of the fine image, and based on the first image information and the second image information, it is also used to acquire defect information of the object under test, wherein the defect information includes at least one of defect location information, defect size information, defect depth information, defect volume information, and defect type information.

[0006] The semiconductor defect detection equipment further includes a polarization detection component, which comprises: The second light source is used to emit an oblique beam, the angle between the oblique beam and the side of the object under test is an acute angle, and the oblique beam is directed at the object under test to form a third beam; A polarizer is used to receive the third beam, and the polarizer is also used to transmit light with a preset polarization direction and form a fourth beam; A polarizing imaging component is used to receive the fourth beam and form a polarized image.

[0007] The semiconductor defect detection equipment also includes a test bench, which is used to hold the object under test. The test stage is capable of moving the test object relative to the schlieren microscope group. And / or, the test stand can fix the object under test.

[0008] A second aspect of this application provides a semiconductor defect detection method, the semiconductor defect detection method comprising: Provide semiconductor defect detection equipment and test object as provided in the first aspect of this application; Place the object to be tested within the observation area; The first light source is controlled to emit a detection beam; wherein the detection beam is directed to the lens assembly and the object under test to form a first beam, the blade assembly receives the first beam, the blade assembly also blocks part of the light flux of the first beam and transmits a second beam, the second beam is refracted by the object under test to form a schlieren image, and the schlieren imaging assembly receives the second beam to form a schlieren image. Based on the schlieren image, determine whether the test object has defects; When it is determined that the object under test has a defect, the differential interference microscope group is controlled to acquire a fine image of the defect location of the object under test and to obtain the defect information of the object under test.

[0009] The step of determining whether the object to be tested has defects includes: Acquire the image information of the schlieren image, the image information including grayscale information, and calculate the grayscale contrast of each region of the object under test; Determine whether the grayscale contrast is within a preset range; When the grayscale contrast is not within the preset range, it is determined that the area corresponding to the grayscale contrast has a defect.

[0010] The step of calculating the grayscale contrast of each region of the object under test includes: The template image information for obtaining the schlieren image of a defect-free template object includes template grayscale information; Based on the template grayscale information, calculate the average grayscale G0 of each region of the defect-free template, and calculate the average grayscale G of each region of the test object. Calculate the grayscale contrast of each region of the object under test, C = (G - G0) / G0.

[0011] The step of determining that the region corresponding to the grayscale contrast has defects further includes: Based on the optical calibration curve of the semiconductor defect detection device, the grayscale contrast of the test object is converted into light deflection angle. The semiconductor defect detection device detects the optical path length of the object under test, and calculates the refractive index gradient based on the light deflection angle and the optical path length. Obtain the relationship coefficient between the material refractive index and depth of the object under test, and obtain the defect information of the object under test based on the refractive index gradient and the relationship coefficient. The defect information includes at least one of defect size information, defect depth information, and defect volume information.

[0012] The semiconductor defect detection equipment further includes a polarization detection component, which comprises: The second light source is used to emit an oblique beam, the angle between the oblique beam and the side of the object under test is an acute angle, and the oblique beam is directed at the object under test to form a third beam; A polarizer is used to receive the third beam, and the polarizer is also used to transmit light with a preset polarization direction and form a fourth beam; A polarizing imaging component for receiving the fourth beam and forming a polarized image; The semiconductor defect detection method further includes: The second light source is controlled to emit an oblique beam; wherein the oblique beam is directed onto the object under test and forms a third beam, the polarizer receives the third beam, the polarizer also transmits light with a preset polarization direction and forms a fourth beam, and the polarized imaging component receives the fourth beam and forms a polarized image; Based on the polarized image, determine whether the side of the object under test has a defect.

[0013] The semiconductor defect detection equipment and method provided in this application employ a semiconductor defect detection device including a first light source, a schlieren microscope group, a schlieren imaging component, and a differential interference microscope group. The device utilizes a lens assembly to refract the density difference formed at the defect location of the test object, and a knife-edge assembly to block irrelevant light flux, thereby enhancing the light refracted due to the density difference at the defect location. This accurately captures the changes in light signals caused by the defect. The schlieren imaging component then forms a schlieren image to locate the defect location, and the differential interference microscope group acquires a detailed image of the defect location to complete the defect detection. This achieves rapid, non-destructive semiconductor detection, improving both the detection efficiency and accuracy while avoiding damage to the test object. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments of this application will be described below.

[0015] Figure 1 This is a schematic diagram of the structure of a semiconductor defect detection device provided in one embodiment of this application.

[0016] Figure 2 This is a schematic diagram of the structure of a semiconductor defect detection device provided in another embodiment of this application.

[0017] Figure 3 A schematic diagram of the structure of a semiconductor defect detection device provided in another embodiment of this application.

[0018] Figure 4 This is a schematic flowchart of a semiconductor defect detection method provided in one embodiment of this application.

[0019] Figure 5 This is a schematic flowchart of a semiconductor defect detection method provided in another embodiment of this application.

[0020] Figure 6 This is a schematic flowchart of a semiconductor defect detection method provided in another embodiment of this application.

[0021] Figure 7 The semiconductor defect detection equipment provided in Embodiment 1 of this application scans the schlieren image of the wafer.

[0022] Figure 8 A fine image of a wafer scanned by the semiconductor defect detection equipment provided in Embodiment 1 of this application.

[0023] Figure 9 A fine image of a wafer scanned by the semiconductor defect detection equipment provided in Embodiment 1 of this application.

[0024] Figure 10The semiconductor defect detection equipment provided in Embodiment 2 of this application scans the schlieren image of the wafer.

[0025] Figure 11 A fine image of a wafer scanned by the semiconductor defect detection equipment provided in Embodiment 2 of this application.

[0026] Figure 12 A fine image of a wafer scanned by the semiconductor defect detection equipment provided in Embodiment 2 of this application.

[0027] Figure 13 A fine image of a wafer scanned by the semiconductor defect detection equipment provided in Embodiment 2 of this application.

[0028] Figure 14 Four fine images of a wafer scanned by the semiconductor defect detection equipment provided in Embodiment 2 of this application.

[0029] Figure 15 Five fine images of a wafer scanned by the semiconductor defect detection equipment provided in Embodiment 2 of this application.

[0030] Figure 16 Six. A fine image of a wafer scanned by the semiconductor defect detection equipment provided in Embodiment 2 of this application.

[0031] Labeling description: Semiconductor defect detection equipment 1, first light source 10, schlieren microscope group 20, lens assembly 21, first schlieren mirror 211, second schlieren mirror 212, observation area 213, blade assembly 22, schlieren imaging assembly 30, processor 40, test stage 50, differential interference microscope group 60, polarization detection assembly 70, test object 100. Detailed Implementation

[0032] The following are preferred embodiments of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

[0033] In view of this, in order to solve the above problems, please refer to the following: Figures 1-2This embodiment provides a semiconductor defect detection device 1, which includes a first light source 10, a schlieren microscope group 20, a schlieren imaging component 30, and a differential interference microscope group 60. The first light source 10 is used to emit a detection beam. The schlieren microscope group 20 includes a lens assembly 21 and a knife-edge assembly 22. The lens assembly 21 has an observation area 213 for accommodating a test object 100. The detection beam is incident on the lens assembly 21 and the test object 100 to form a first beam. The knife-edge assembly 22 receives the first beam and also blocks part of the light flux of the first beam and transmits a second beam. The second beam is refracted by the test object 100. The schlieren imaging component 30 is used to receive the second beam and form a schlieren image. The differential interference microscope group 60 is used to acquire a fine image of the defect location on the test object 100.

[0034] The test object 100 can be a wafer or a semiconductor. Optionally, the material of the test object 100 includes at least one of silicon carbide, gallium nitride, gallium arsenide, and indium phosphide.

[0035] Semiconductor defect detection equipment 1 can be applied to the detection of surface or internal specific defects in compound semiconductor wafers and semiconductor-related devices, such as buried cracks, microbubbles, lattice defects, and grinding marks. Furthermore, semiconductor defect detection equipment 1 can be applied to the detection of surface or internal specific defects in compound semiconductor wafers and semiconductor-related devices in the fields of automotive power devices and high-frequency communication devices.

[0036] Specifically, the first light source 10 is used to emit a detection beam. Optionally, the first light source 10 is a point light source 10. Optionally, the first light source 10 is a xenon first light source 10.

[0037] The schlieren microscope assembly 20 includes a lens assembly 21 and a blade assembly 22. Optionally, the blade assembly 22 is positioned further away from the first light source 10 than the lens assembly 21.

[0038] Since the non-uniform state of a transparent solid can be mapped as a density gradient, this embodiment utilizes the schlieren microscope group 20 and the schlieren imaging component 30 to work together to convert the small refractive index change caused by the density difference at the defect of the test object 100 into a large brightness difference for observation.

[0039] Furthermore, the lens assembly 21 includes a first schlieren mirror 211 and a second schlieren mirror 212. The first schlieren mirror 211 is disposed on one side of the first light source 10 and is used to collimate the detection beam. The second schlieren mirror 212 is disposed between the first schlieren mirror 211 and the blade assembly 22. The observation area 213 is located between the first schlieren mirror 211 and the second schlieren mirror 212 and is used to focus the detection beam and form the first beam.

[0040] The first schlieren mirror 211 is used to collimate the detection beam. For example, it collimates the detection beam from the point first light source 10 to a parallel beam state. Further optionally, the first schlieren mirror 211 is selected from a convex lens or a concave mirror.

[0041] When the first schlieren mirror 211 is selected from a concave mirror, the concave surface of the concave mirror is set towards the object to be measured 100.

[0042] The second schlieren mirror 212 is used to converge the light beam.

[0043] Alternatively, the second schlieren lens 212 is selected from a convex lens, with the convex surface of the convex lens facing the object to be measured 100.

[0044] For example, the first schlieren 211 is selected from a convex lens, and the second schlieren 212 is selected from a convex lens.

[0045] Alternatively, the first schlieren 211 may be selected from a concave mirror, and the second schlieren 212 may be selected from a convex lens.

[0046] Both of the above designs are suitable for miniaturized and standardized optical path designs for semiconductor inspection. They can reduce the selection difficulty and assembly complexity of the lens assembly 21 while ensuring collimation and focusing effects, taking into account the practicality and economy of the semiconductor defect inspection equipment 1, and can stably achieve the optical conditions required by the schlieren method.

[0047] The observation area 213 is located between the first schlieren mirror 211 and the second schlieren mirror 212.

[0048] In the semiconductor defect detection process: First, the test object 100 is placed in the observation area 213; then, the position of the test object 100 is adjusted so that it is located in the optical path; next, focusing is performed so that the point light source 10 is located at the focal point of the first schlieren mirror 211; subsequently, the detection beam is used to scan each area of ​​the test object 100, and finally, a schlieren image is formed.

[0049] Optionally, the object under test 100 is set perpendicular to the optical axis; or, the object under test 100 is set at an angle relative to the optical axis to avoid interference from reflected light. For example, the object under test 100 is slightly tilted relative to the optical axis.

[0050] The knife-edge assembly 22 is used to block part of the light flux of the first beam and allow the second beam to pass through, which is refracted by the object under test 100. Optionally, the knife-edge assembly 22 is disposed between the second schlieren mirror 212 and the schlieren imaging assembly 30.

[0051] Specifically, the blade assembly 22 is used to block the background light that has not been deflected, and to transmit the defect light that has been deflected due to the density difference at the defect of the test object 100, thereby forming a second beam of light.

[0052] The schlieren imaging component 30 is used to receive light and form a schlieren image.

[0053] Optionally, the schlieren imaging assembly 30 includes a CCD camera and an anti-reflection imaging module. The schlieren imaging assembly 30 is capable of accurately capturing changes in the light signal caused by defects.

[0054] It should be noted that schlieren is a method of observation that converts the small refractive index changes caused by the density gradient into a large difference in brightness caused by parallel light.

[0055] In the semiconductor defect detection device 1, the object under test 100 is placed in the observation area 213. The first schlieren mirror 211 allows parallel light to pass through the observation area 213, and the second schlieren mirror 212 causes the parallel light refracted by the density difference of the object under test 100 to converge again. Then, the blade assembly 22 cuts the main light flux, allowing only the light refracted by the object under test 100 to pass through. The schlieren imaging assembly 30 then converts the light signal into a schlieren image. Therefore, the semiconductor defect detection device 1 provided in this embodiment can convert the refraction of light caused by the density difference at the defect of the object under test 100 into the brightness difference of the image, thereby realizing the detection of semiconductor defects.

[0056] The differential interference microscope group 60 can use polarized light interference technology to convert the tiny optical path difference in the object under test 100 into a visible intensity change, thereby producing a high-contrast image with a pseudo-three-dimensional relief effect.

[0057] Specifically, the defect location of the test object 100 can be located based on the schlieren image, and the relative movement of the test object 100 and the differential interference microscope group 60 can be controlled based on the defect location so that the differential interference microscope group 60 can acquire a fine image of the defect location of the test object 100.

[0058] Optionally, the semiconductor defect detection method is as follows: First, the test object 100 is placed in the observation area 213.

[0059] Then, adjust the position of the object under test 100 so that it is located in the optical path.

[0060] Next, focusing is performed so that the first point light source 10 is located at the focal point of the first schlieren mirror 211.

[0061] Subsequently, the detection beam is used to scan various areas of the test object 100; wherein, the detection beam is directed to the first schlieren mirror 211, which collimates the detection beam into parallel light and passes through the observation area 213; the second schlieren mirror 212 causes the parallel light to be refracted by the density difference of the test object 100 and then converges to form the first beam; the blade assembly 22 receives the first beam and cuts the main light flux, allowing only the second beam to pass through; the second beam is refracted by the test object 100 to form the second beam; and the schlieren imaging assembly 30 converts the light signal into a schlieren image.

[0062] Then, the processor 40 acquires the first image information of the schlieren image and determines whether the test object 100 has defects based on the first image information of the schlieren image.

[0063] When it is determined that the test object 100 has a defect, the differential interference microscope group 60 is controlled to acquire a fine image of the defect of the test object 100 and acquire the defect information of the test object 100.

[0064] For example, when it is determined that the test object 100 has a defect, the location of the defect in the test object 100 can be obtained by visual inspection or calculation, and the differential interference microscope group 60 can be controlled to acquire a fine image of the defect location in the test object 100. The fine image can be compared with the defect information of the test object 100, thereby further improving the accuracy of semiconductor defect detection.

[0065] In summary, the semiconductor defect detection device 1 provided in this embodiment, by employing a semiconductor defect detection device 1 including a first light source 10, a schlieren microscope group 20, a schlieren imaging component 30, and a differential interference microscope group 60, utilizes the lens component 21 to refract the density difference formed at the defect of the test object 100, and uses the blade component 22 to block irrelevant light flux, thereby enhancing the light refracted due to the density difference at the defect of the test object 100, accurately capturing the changes in light signals caused by the defect, and then uses the schlieren imaging component 30 to form a schlieren image to locate the defect of the test object 100, and uses the differential interference microscope group 60 to acquire a fine image of the defect, thereby completing the defect detection of the test object 100, realizing non-destructive and rapid semiconductor defect detection, which not only improves the detection efficiency and detection accuracy of semiconductor defect detection, but also avoids damage to the test object 100.

[0066] Please refer to this as well. Figures 1-2 In one embodiment, the semiconductor defect detection device 1 further includes a processor 40, which is electrically connected to the schlieren imaging assembly 30 and the differential interference microscope assembly 60.

[0067] The processor 40 is used to acquire first image information of the schlieren image and second image information of the fine image, and based on the first image information and the second image information, it is also used to acquire defect information of the test object 100, wherein the defect information includes at least one of defect location information, defect size information, defect depth information, defect volume information, and defect type information.

[0068] The processor 40 can acquire the first image information of the schlieren image and the second image information of the fine image, thereby acquiring the defect information of the test object 100, such as the position information of the defect on the test object 100, the radial size information of the defect, the depth information of the defect, the volume information of the defect, and the type information of the defect.

[0069] The types of defects include, but are not limited to, cracks, scratches, abrasions, holes, gaps, impurities, etc., and this embodiment does not limit them.

[0070] Optionally, the semiconductor defect detection equipment 1 further includes a display device electrically connected to the processor 40, the display device having an online operating system for controlling the first light source 10, the schlieren microscope group 20, the schlieren imaging component 30, the test stage 50, and the polarization detection component 70. For example, the display device is a computer.

[0071] Therefore, this embodiment obtains the defect information of the test object 100 by processing the first image information of the schlieren image and the second image information of the fine image, thereby realizing the automated and quantitative analysis of semiconductor defect detection, replacing manual interpretation, reducing the false negative rate and subjective error, and improving the accuracy of the detection results. This facilitates the classification of the test object 100 in subsequent processing, thereby improving processing efficiency and yield.

[0072] Please refer to this as well. Figures 1-3 In one embodiment, the semiconductor defect detection device 1 further includes a polarization detection component 70, which includes a second light source, a polarizer, and a polarization imaging component. The second light source is used to emit an oblique beam, the angle between the oblique beam and the side of the test object 100 is an acute angle, and the oblique beam is incident on the test object 100 to form a third beam. The polarizer is used to receive the third beam and is also used to transmit light with a preset polarization direction to form a fourth beam. The polarization imaging component is used to receive the fourth beam and form a polarized image.

[0073] Optionally, the wavelength range of the second light source is 450nm to 470nm, and the second light source is blue light. This embodiment uses a second light source with a wavelength range of 450nm to 470nm to enhance the resolution of short-wavelength scattering for small defects.

[0074] Optionally, the second light source is arranged in a ring. More optionally, the second light source adopts a ring light guide structure, such as an optical fiber bundle or a light guide plate, to uniformly distribute the LED light on the ring light guide structure.

[0075] Optionally, the angle between the oblique beam and the side of the object under test 100 is 20° to 70°, specifically, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, or 70°, etc.

[0076] Therefore, by limiting the angle between the oblique beam and the side surface of the test object 100 to an acute angle, this embodiment further optimizes the detection effect of defects on the side surface of the test object 100 and improves the accuracy of semiconductor defect detection.

[0077] The polarizer can rotate from 0° to 360° to control the polarization state of light, allowing light with a preset polarization direction to pass through, thereby improving the contrast and sensitivity of defect detection.

[0078] The polarization imaging component includes a CCD camera, which can accurately capture changes in light signals caused by defects.

[0079] In related technologies, the main focus is on inspecting the surface morphology of the front and back sides of wafers, but the ability to detect defects on the sides of wafers, such as vertical scratches, edge chipping, and sidewall roughness, is insufficient. Because the surface orientation of side defects is perpendicular to the principal optical axis, the reflected signal is weak and the contrast is low under parallel light illumination, making them difficult to detect.

[0080] Specifically, the oblique beam of light produces specular reflection on the side of the object under test 100, and the polarization state of the reflected light is related to the incident surface. If there is a defect on the side of the object under test 100, the defect will cause a change in the local surface orientation, disrupting the regularity of the reflected polarization. Therefore, by analyzing the polarization rotation and extinction characteristics of the reflected light, side defects can be identified.

[0081] Optionally, the processor 40 is electrically connected to the polarization detection component 70. The processor 40 is used to acquire polarization images and to determine whether the side of the object under test 100 has defects based on the polarization images.

[0082] Therefore, this embodiment, by setting up a polarized light detection component 70, specifically targets the imaging detection of side defects in semiconductors, making up for the shortcomings of schlieren and differential interferometry in detecting side defects. It achieves full coverage detection of defects in the front, back, and sides of the test object 100, further improving the accuracy of semiconductor defect detection and further reducing the missed detection rate of semiconductor defects.

[0083] Please refer to this as well. Figures 1-3In one embodiment, the semiconductor defect detection device 1 further includes a test stage 50, which is used to hold the object under test 100.

[0084] The test stage 50 is capable of moving the test object 100 relative to the schlieren microscope group 20.

[0085] And / or, the test stand 50 can fix the test object 100.

[0086] The test stage 50 can move the test object 100 along the X-axis, Y-axis and Z-axis, thereby adjusting the position of the test object 100.

[0087] Optionally, the test stage 50 uses vacuum adsorption to fix the test object 100. Further optionally, the test stage 50 is provided with a vacuum chamber to create a vacuum environment for adsorbing the test object 100.

[0088] Therefore, by enabling the test stage 50 to move the test object 100, this embodiment can adapt to test objects 100 of different sizes and thicknesses, achieve precise alignment, realize accurate scanning of the entire surface without dead angles, and improve the accuracy of semiconductor defect detection. Furthermore, this embodiment can also fix the test object 100 to prevent it from shifting during the detection process, further improving the accuracy of semiconductor defect detection.

[0089] Please refer to this as well. Figures 1-4 This application also provides a semiconductor defect detection method, the semiconductor defect detection method comprising: S100 provides a semiconductor defect detection device 1 and a test object 100 as described above in this application.

[0090] The semiconductor defect detection equipment 1 and the test object 100 are as described above in this application, and will not be repeated here.

[0091] S200, the object to be tested 100 is placed in the observation area 213.

[0092] S300, control the first light source 10 to emit a detection beam; wherein, the detection beam is directed to the lens assembly 21 and the object under test 100 to form a first beam, the blade assembly 22 receives the first beam, the blade assembly 22 also blocks part of the light flux of the first beam and transmits a second beam, the second beam is refracted by the object under test 100 to form a schlieren image, and the schlieren imaging assembly 30 receives the second beam and forms a schlieren image.

[0093] S400, based on the schlieren image, determine whether the test object 100 has defects.

[0094] S500, when it is determined that the object under test 100 has a defect, the differential interference microscope group 60 is controlled to acquire a fine image of the defect of the object under test 100 and acquire the defect information of the object under test 100.

[0095] Specifically, first, the object to be tested 100 is placed in the observation area 213.

[0096] Then, adjust the position of the object under test 100 so that it is located in the optical path.

[0097] Next, focusing is performed so that the first point light source 10 is located at the focal point of the first schlieren mirror 211.

[0098] Subsequently, the detection beam is used to scan various areas of the test object 100; wherein, the detection beam is directed to the first schlieren mirror 211, which collimates the detection beam into parallel light and passes through the observation area 213; the second schlieren mirror 212 causes the parallel light to be refracted by the density difference of the test object 100 and then converges to form the first beam; the blade assembly 22 receives the first beam and cuts the main light flux, allowing only the second beam to pass through; the second beam is refracted by the test object 100 to form the second beam; and the schlieren imaging assembly 30 converts the light signal into a schlieren image.

[0099] Then, the processor 40 acquires the first image information of the schlieren image and determines whether the test object 100 has defects based on the first image information of the schlieren image.

[0100] When it is determined that the test object 100 has a defect, the differential interference microscope group 60 is controlled to acquire a fine image of the defect of the test object 100 and acquire the defect information of the test object 100.

[0101] For example, when it is determined that the test object 100 has a defect, the location of the defect in the test object 100 can be obtained by visual inspection or calculation, and the differential interference microscope group 60 can be controlled to acquire a fine image of the defect location in the test object 100. The fine image can be compared with the defect information of the test object 100, thereby further improving the accuracy of semiconductor defect detection.

[0102] Defect information includes at least one of the following: defect location information, defect size information, defect depth information, defect volume information, and defect type information.

[0103] In summary, the semiconductor defect detection method provided in this embodiment, by employing the semiconductor defect detection device 1 provided above in this application, utilizes a semiconductor defect detection device 1 including a first light source 10, a schlieren microscope group 20, a schlieren imaging component 30, and a differential interference microscope group 60. The device 1 uses a lens assembly 21 to refract the density difference formed at the defect location of the test object 100, and uses a blade assembly 22 to block irrelevant light flux, thereby enhancing the light refracted due to the density difference at the defect location of the test object 100. This accurately captures the changes in light signals caused by the defect. The schlieren imaging component 30 then forms a schlieren image to locate the defect location of the test object 100, and the differential interference microscope group 60 acquires a detailed image of the defect location to complete the defect detection of the test object 100. This achieves rapid, non-destructive semiconductor detection, improving both the detection efficiency and accuracy of semiconductor defect detection while avoiding damage to the test object 100.

[0104] Please refer to this as well. Figures 1-5 In one embodiment, step S400 of determining whether the test object 100 has a defect includes: S410, acquire the image information of the schlieren image, the image information including grayscale information, and calculate the grayscale contrast of each region of the test object 100.

[0105] S420, determine whether the grayscale contrast is within a preset range.

[0106] S430, when the grayscale contrast is not within the preset range, it is determined that the area corresponding to the grayscale contrast has a defect.

[0107] For example, if the grayscale contrast of the first region of the test object 100 is within a preset range, then the first region is determined to be without defects.

[0108] For example, if the grayscale contrast of the second region of the test object 100 is not within the preset range, then the second region is judged to have a defect.

[0109] Since schlieren is a method of observation that converts small changes in refractive index caused by density gradient into large differences in brightness caused by parallel light, the greater the grayscale contrast, and the fact that the grayscale contrast is not within the preset range, it indicates that the refractive index of the test object 100 in that region has a significant change, or in other words, the refractive index difference of the test object 100 in that region is huge, and that the test object 100 in that region has a defect.

[0110] Therefore, this embodiment calculates the grayscale contrast and compares it with a preset range to determine whether the region has a defect. It converts the visual differences in the schlieren image into quantitative values, which not only standardizes and objectifies defect identification and improves the accuracy of semiconductor defect detection, but also allows for rapid location of defective regions, improving the efficiency and accuracy of defect identification.

[0111] Further, step S410, which calculates the grayscale contrast of each region of the object under test 100, includes: S411, Obtain template image information of the schlieren image of the defect-free template, wherein the image information includes template grayscale information.

[0112] S412, based on the template grayscale information, calculate the average grayscale G0 of each region of the defect-free template, and calculate the average grayscale G of the corresponding region of the test object 100.

[0113] S413, calculate the grayscale contrast C = (G - G0) / G0 of the area corresponding to the test object 100.

[0114] For example, if the template grayscale information is sampled as [125, 128, 126, 127, 129], then the average grayscale G0 of this area of ​​the defect-free template is (125+128+126+127+129) / 5=127. The grayscale information sampling of the test object 100 is [140, 142, 138, 141, 139]. Then the average grayscale G of the corresponding area of ​​the test object 100 is (140+142+138+141+139) / 5=140. The grayscale contrast of the area corresponding to the test object 100 is C = (G-G0) / G0 = (140-127) / 127 = 10.2%, and the preset range is 0~±10%. Therefore, the grayscale contrast of the corresponding area is not within the preset range, so it is determined that the area corresponding to the grayscale contrast has a defect.

[0115] Optionally, the preset range is 0 to ±10%, and further optionally, the preset range is 0 to ±5%.

[0116] Furthermore, when the grayscale contrast is not within the preset range and the grayscale contrast C of the corresponding area of ​​the test object 100 is greater than 0, the positive contrast indicates that the defect is brighter and the light is deflected in the opposite direction to the blade assembly 22. The defect type is a protrusion with high density.

[0117] When the grayscale contrast is not within the preset range and the grayscale contrast C of the corresponding area of ​​the test object 100 is less than 0, the negative contrast indicates that the defect is darker and the light is deflected towards the blade assembly 22. The defect type is a depression with low density.

[0118] Therefore, by introducing the grayscale information of the defect-free template as a benchmark, this embodiment calculates the grayscale contrast of the corresponding area of ​​the test object 100, which can eliminate the influence of system errors such as equipment optical path and ambient light on the detection results, further improve the reliability of using grayscale contrast to determine whether there is a defect, and further improve the accuracy of semiconductor defect detection.

[0119] Further, after step S430 of determining that the region corresponding to the grayscale contrast has defects, the method further includes: S431, based on the optical calibration curve of the semiconductor defect detection device 1, the grayscale contrast of the test object 100 is converted into the light deflection angle.

[0120] S432, the semiconductor defect detection device 1 detects the optical path length of the test object 100, and calculates the refractive index gradient based on the light deflection angle and the optical path length.

[0121] S433, obtain the relationship coefficient between the material refractive index and the depth of the test object 100, and obtain the defect information of the test object 100 based on the refractive index gradient and the relationship coefficient. The defect information includes at least one of defect size information, defect depth information, and defect volume information.

[0122] Since the schlieren method is a method of observation that converts the small refractive index change caused by the density gradient into a large difference in brightness caused by parallel light, this implementation method corresponds grayscale contrast with the light deflection angle, and then calculates the refractive index gradient at the defect of the test object 100 based on the light deflection angle, thereby obtaining the quantitative information of the defect of the test object 100, including defect size information, defect depth information, defect volume information, etc.

[0123] Therefore, this embodiment obtains the defect information of the test object 100 by using grayscale contrast, corresponding to light deflection angle and refractive index gradient, and realizes accurate conversion from schlieren image to semiconductor defect physical parameters. It can quantitatively obtain key information such as defect size, defect depth and defect volume, and is applicable to more application scenarios, meeting the needs of refined detection and analysis of semiconductor defects.

[0124] Please refer to this as well. Figures 1-6In one embodiment, the semiconductor defect detection device 1 further includes a polarization detection component 70, which includes a second light source, a polarizer, and a polarization imaging component. The second light source is used to emit an oblique beam, the angle between the oblique beam and the side of the test object 100 is an acute angle, and the oblique beam is incident on the test object 100 to form a third beam. The polarizer is used to receive the third beam and is also used to transmit light with a preset polarization direction to form a fourth beam. The polarization imaging component is used to receive the fourth beam and form a polarized image.

[0125] The polarization detection component 70 is as described above in this application, and will not be repeated here.

[0126] The semiconductor defect detection method further includes: S610, control the second light source to emit an oblique beam; wherein, the oblique beam is directed to the object under test 100 and forms a third beam, the polarizer receives the third beam, the polarizer also transmits light with a preset polarization direction and forms a fourth beam, the polarization imaging component receives the fourth beam and forms a polarized image.

[0127] S620, Based on the polarized image, determine whether the side of the object to be tested 100 has a defect.

[0128] Specifically, the oblique beam is controlled to scan the side of the test object 100; wherein, the oblique beam is directed to the side of the test object 100 and forms a third beam, the polarizer receives the third beam, the polarizer also transmits light with a preset polarization direction and forms a fourth beam, the polarization imaging component receives the fourth beam and converts the light signal into a polarized image.

[0129] Then, the processor 40 acquires the image information of the polarized image and determines whether the side of the test object 100 has defects based on the image information of the polarized image.

[0130] Therefore, this embodiment utilizes the polarization detection component 70 to image and detect side defects in semiconductors, thus overcoming the shortcomings of schlieren and differential interferometry in detecting side defects. This achieves full coverage detection of defects in the front, back, and sides of the test object 100, further improving the accuracy of semiconductor defect detection and reducing the missed detection rate of semiconductor defects.

[0131] In one embodiment, the test object 100 includes a first end and a second end opposite to each other, and there are multiple rows of sub-regions arranged along an arrangement direction perpendicular to the first end and the second end between the first end and the second end.

[0132] Step S300, which controls the light source to emit a detection beam, includes: S310, control the detection beam to scan the Nth row sub-region of the test object 100 along the arrangement direction from the first end to the second end, where N is a positive integer.

[0133] S320, control the detection beam to scan the N+1th row sub-region of the test object 100 along the arrangement direction from the second end to the first end.

[0134] S330, control the detection beam to scan the N+2th row sub-region of the test object 100 along the arrangement direction from the first end to the second end.

[0135] For example, the first end and the second end can also be understood as the left side and the right side. The detection beam is controlled to scan the Nth row sub-region of the test object 100 in a direction from left to right. Then, the detection beam is controlled to scan the N+1th row of the test object 100 in a direction from right to left; Subsequently, the detection beam is controlled to scan the N+2th row of the test object 100 in a left-to-right direction.

[0136] This can also be understood as controlling the detection beam to scan the test object 100 along an S-shaped scanning path.

[0137] Therefore, by employing a reciprocating line-by-line scanning method to detect sub-regions of the test object 100, this embodiment not only avoids missed detections caused by single-line unidirectional scanning, ensuring uniform and continuous coverage of the entire test object 100 with the detection beam, but also improves the detection speed of the entire test object 100 and enhances the detection efficiency of semiconductor defects.

[0138] To make the objectives and advantages of this application clearer, the effects of the semiconductor defect detection method of this application will be further explained in detail below with reference to specific embodiments.

[0139] Example 1: Taking an 8-inch SiC wafer as an example, first place the 8-inch SiC wafer in the center of the test stage 50, then adjust the schlieren microscope group 20 to the edge of the wafer for focusing. After focusing, a wide-angle full-coverage scan can be performed, with a total scanning time of less than one minute.

[0140] Subsequently, a schlieren image of the entire wafer, composed of multiple parts and pieces pieced together from these parts, is generated, such as... Figure 7 As shown. Therefore, by using the semiconductor defect detection equipment 1 and detection method provided in this application, high-speed scanning of an 8-inch wafer with a wide field of view of ≥10mm diameter and a time of ≤1min can be achieved.

[0141] Then, local detection was performed using the differential interference microscope group 60, such as... Figure 8 , Figure 9As shown, local bright / dark field precision measurement is performed for specific defects, with a pixel resolution better than 1μm and a detectable minimum feature size ≤1μm.

[0142] Example 2: Taking a 6-inch LT wafer as an example, the operation steps are as described in Example 1 above. The detected schlieren image is as follows. Figure 10 As shown, local detection is performed using the differential interference microscope group 60. Figures 11-16 As shown, in Figure 11 The semiconductor defect is a minor scratch. Figure 12 In semiconductors, defects are cracks. Figure 13 The semiconductor defect is scratching. Figure 14 In semiconductors, defects are holes. Figure 15 In semiconductors, defects are gaps. Figure 16 Semiconductor defects are impurities. It is evident that using a differential interference microscope group 60 in conjunction with a schlieren microscope group 20 can quickly obtain detailed images of semiconductor defects and identify the defect type.

[0143] In summary, compared with traditional automated optical inspection (AOI) or bright-field and dark-field inspection methods, the schlieren microscope group 20 does not rely on the difference in reflection intensity, but is highly sensitive to the density difference of the test object 100. Therefore, it can effectively identify minor scratches, polishing marks, CMP residues and thin film inhomogeneities from the nanometer to the micrometer level, and is especially suitable for high reflectivity and mirror-like wafer surfaces.

[0144] Its main advantages are: first, it is a non-contact detection method that does not damage the sample and is suitable for online high-speed detection; second, it has an amplification effect on minute morphological changes, which can significantly improve the defect detection capability; and third, the system structure is relatively simple and can be integrated with existing automated optical inspection (AOI) equipment to achieve high-throughput detection.

[0145] Therefore, the semiconductor defect detection equipment 1 and semiconductor defect detection method provided in this application construct an integrated wafer defect detection solution, solving the problems of difficulty in balancing wide-angle field of view and local precision measurement, and incomplete defect coverage.

[0146] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings: In this application, terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0147] In this application, "one or more" refers to any one, any two, or any two or more of the listed items. "Several" refers to any two or more.

[0148] In this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0149] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0150] In this application, the terms "embodiment" and "implementation" mean that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of these phrases in various locations throughout the specification does not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this application can be combined with other embodiments. Furthermore, it should be understood that the features, structures, or characteristics described in the various embodiments of this application can be arbitrarily combined to form yet another embodiment that does not depart from the spirit and scope of the technical solution of this application, provided there is no contradiction between them.

[0151] The above description represents some embodiments of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

Claims

1. A semiconductor defect detection device, characterized in that, The semiconductor defect detection equipment includes: The first light source is used to emit the detection beam; A schlieren microscope assembly includes a lens assembly and a blade assembly. The lens assembly has an observation area for accommodating an object to be tested. A detection beam is incident on the lens assembly and the object to be tested to form a first beam. The blade assembly receives the first beam and also blocks a portion of the light flux of the first beam while allowing a second beam to pass through. The second beam is refracted by the object to be tested. A schlieren imaging component for receiving the second beam and forming a schlieren image; The differential interference microscope array is used to acquire fine images of the defects in the object under test.

2. The semiconductor defect detection equipment as described in claim 1, characterized in that, The lens assembly includes: A first schlieren lens is disposed on one side of the first light source, and the first schlieren lens is used to collimate the detection beam. A second schlieren lens is disposed between the first schlieren lens and the blade assembly. The observation area is located between the first schlieren lens and the second schlieren lens. The second schlieren lens is used to focus the detection beam and form the first beam.

3. The semiconductor defect detection device as described in claim 1, characterized in that, The semiconductor defect detection device further includes a processor, which is electrically connected to the schlieren imaging component and the differential interference microscope group; The processor is used to acquire first image information of the schlieren image and second image information of the fine image, and based on the first image information and the second image information, it is also used to acquire defect information of the object under test, wherein the defect information includes at least one of defect location information, defect size information, defect depth information, defect volume information, and defect type information.

4. The semiconductor defect detection device as described in claim 1, characterized in that, The semiconductor defect detection equipment further includes a polarization detection component, which comprises: The second light source is used to emit an oblique beam, the angle between the oblique beam and the side of the object under test is an acute angle, and the oblique beam is directed at the object under test to form a third beam; A polarizer is used to receive the third beam, and the polarizer is also used to transmit light with a preset polarization direction and form a fourth beam; A polarizing imaging component is used to receive the fourth beam and form a polarized image.

5. The semiconductor defect detection device as described in claim 1, characterized in that, The semiconductor defect detection equipment also includes a test stand, which is used to hold the object under test. The test stage is capable of moving the test object relative to the schlieren microscope group. And / or, the test stand can fix the object under test.

6. A semiconductor defect detection method, characterized in that, The semiconductor defect detection method includes: Provides the semiconductor defect detection equipment and test object as described in claim 1; Place the object to be tested within the observation area; The first light source is controlled to emit a detection beam; wherein the detection beam is directed to the lens assembly and the object under test to form a first beam, the blade assembly receives the first beam, the blade assembly also blocks part of the light flux of the first beam and transmits a second beam, the second beam is refracted by the object under test to form a schlieren image, and the schlieren imaging assembly receives the second beam to form a schlieren image. Based on the schlieren image, determine whether the test object has defects; When it is determined that the object under test has a defect, the differential interference microscope group is controlled to acquire a fine image of the defect location of the object under test and to obtain the defect information of the object under test.

7. The semiconductor defect detection method as described in claim 6, characterized in that, The steps for determining whether the test object has defects include: Acquire the image information of the schlieren image, the image information including grayscale information, and calculate the grayscale contrast of each region of the object under test; Determine whether the grayscale contrast is within a preset range; When the grayscale contrast is not within the preset range, it is determined that the area corresponding to the grayscale contrast has a defect.

8. The semiconductor defect detection method as described in claim 7, characterized in that, The steps for calculating the grayscale contrast of each region of the object under test include: The template image information for obtaining the schlieren image of a defect-free template object includes template grayscale information; Based on the template grayscale information, calculate the average grayscale G0 of each region of the defect-free template, and calculate the average grayscale G of each region of the test object. Calculate the grayscale contrast of each region of the object under test, C = (G - G0) / G0.

9. The semiconductor defect detection method as described in claim 7, characterized in that, After the step of determining that the region corresponding to the grayscale contrast has defects, the method further includes: Based on the optical calibration curve of the semiconductor defect detection device, the grayscale contrast of the test object is converted into light deflection angle. The semiconductor defect detection device detects the optical path length of the object under test, and calculates the refractive index gradient based on the light deflection angle and the optical path length. Obtain the relationship coefficient between the material refractive index and depth of the object under test, and obtain the defect information of the object under test based on the refractive index gradient and the relationship coefficient. The defect information includes at least one of defect size information, defect depth information, and defect volume information.

10. The semiconductor defect detection method as described in claim 6, characterized in that, The semiconductor defect detection equipment further includes a polarization detection component, which comprises: The second light source is used to emit an oblique beam, the angle between the oblique beam and the side of the object under test is an acute angle, and the oblique beam is directed at the object under test to form a third beam; A polarizer is used to receive the third beam, and the polarizer is also used to transmit light with a preset polarization direction and form a fourth beam; A polarizing imaging component for receiving the fourth beam and forming a polarized image; The semiconductor defect detection method further includes: The second light source is controlled to emit an oblique beam; wherein the oblique beam is directed onto the object under test and forms a third beam, the polarizer receives the third beam, the polarizer also transmits light with a preset polarization direction and forms a fourth beam, and the polarized imaging component receives the fourth beam and forms a polarized image; Based on the polarized image, determine whether the side of the object under test has a defect.

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