A method for detecting micropipe defects in silicon carbide substrates

Abstract

The present invention relates to a method for detecting micro-pipe defects in a silicon carbide substrate, comprising the following steps: S1, preparing a laser detection instrument; S2, taking a silicon carbide substrate to be detected, placing it on the sample rotating system, using the laser detection instrument to emit laser, focusing on the upper and lower surfaces of the silicon carbide substrate for scanning, obtaining the size and position of the upper micro-pipe defects M1 and M2 on the bottom surface of the silicon carbide substrate, and the size and position of the micro-pipe defect M5 on the lower surface; S3, using the laser detection instrument to emit laser, focusing the laser on the silicon carbide substrate body below the upper surface of the silicon carbide substrate for scanning, obtaining the size and position of the micro-pipe defects M3 and M4 in the silicon carbide substrate body; S4, connecting the defect morphologies M1 to M5, forming a morphology map of the micro-pipe defects and outputting it. The method can automatically identify micro-pipe defects in silicon carbide substrates, and can also distinguish micro-pipe defects from other defects in silicon carbide substrates, and has a good application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of silicon carbide defect detection and discloses a method for detecting micro-pipe defects in a silicon carbide substrate. Background Art

[0002] In the manufacturing of SiC devices, different surface defects are formed during the formation of SiC epitaxial layers. The most important defects are called "microtubes", three-dimensional microtubes with a characteristic size of 30 to 40 um or "pinholes". The most common microtubes are small holes with a size of 0.1 to 5 um, which can penetrate into the epitaxial layer. The density of microtubes is 10 to 10 3 / cm 2 Most micropipes are formed by several screw dislocations clustered together. The above causes "micropipes" to be often called "device killer defects" and are also the main defects in the SiC device development process.

[0003] At present, the identification of micro-pipe defects in silicon carbide is carried out by naked eye observation under a microscope. The surface of the silicon carbide substrate to be tested is divided into several small square areas, and each small area is numbered; the center point of the area is taken as the measurement point, and the number of micro-pipes in each field of view area is measured and recorded with a microscope to obtain the total number of micro-pipes on the surface of the silicon carbide substrate to be tested within the field of view area, and then the micro-pipe density of the entire silicon carbide substrate is obtained.

[0004] However, to inspect a complete 4-inch, 6-inch or even 8-inch silicon carbide substrate, under the magnification of the microscope that can clearly observe micropipe defects, the tester needs to calibrate the defects in hundreds of viewing areas on a silicon carbide substrate. In addition, the tester must move the field of view, focus, and finally mark on the drawing. The whole process is time-consuming, labor-intensive and prone to errors, which reduces the accuracy of the test results. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems existing in the existing manual detection of silicon carbide defects and provide a method for detecting micropipe defects in a silicon carbide substrate. The laser beam generated by a laser detection instrument is used to perform a frontal scan on the surface and body of the silicon carbide substrate to be tested, and the signal intensity and position of the reflected light from the surface and body are collected and determined, so as to obtain the total number and distribution of micropipe defects in the silicon carbide substrate, form a defect distribution map and output it, which has the advantages of automatic recognition, rapid detection and high accuracy.

[0006] The specific plan is as follows:

[0007] A method for detecting micropipe defects in a silicon carbide substrate comprises the following steps:

[0008] S1, prepare a laser detection instrument, the laser detection instrument includes: a) a laser emitter and a polarizer; b) a reflection imaging detector and a four-quadrant detector; c) a vacuum system and a cooling system, a sample rotation system and a track system for moving the light source; d) a thickness detector, an image acquisition device and an image analysis system, the image analysis system performs analysis based on the surface defect distribution map output;

[0009] The polarizer is connected to the laser emitter, so that the laser generated by the laser emitter passes through the polarizer and irradiates the silicon carbide substrate placed on the horizontal carrier at a certain incident angle; the laser beam signal reflected by the silicon carbide substrate is collected by the reflection imaging detector and the four-quadrant detector, and after the information is collected, it is sent to the image analysis system, and the image analysis system combines the detection results of the thickness detector and the image acquisition device to perform image analysis to form a surface defect distribution map;

[0010] S2, take the silicon carbide substrate to be inspected, place it on the sample rotation system, use the laser detection instrument to emit laser, focus on the upper surface and lower surface of the silicon carbide substrate for scanning, the laser emitter emits laser, irradiates the silicon carbide substrate, the laser passes through the surface and the inside of the silicon carbide substrate and will be reflected, the four-quadrant detector collects the reflection signal and the reflection spot position signal, and analyzes the received signal, and then identifies the size and position of the upper surface micropipe defects M1 and M2 on the bottom surface of the silicon carbide substrate, and the size and position of the micropipe defect M5 on the lower surface; wherein the micropipe defects M1 and M2 are respectively located on the incident line and the reflection line of a certain laser light, M1 is the initial stage of scanning the upper surface in step S2, and the laser The laser passes through the upper surface of the silicon carbide substrate and reflects on the lower surface of the silicon carbide substrate. The reflected signal is blocked by the defect. The four-quadrant detector only receives the reflected signal from the upper surface but cannot receive the reflected signal from the lower surface, forming a black defect morphology. M2 is the end stage of scanning the upper surface in step S2. The laser scans a defect on the upper surface of the silicon carbide substrate, and the four-quadrant detector cannot receive any signal, forming a black defect morphology. M5 is the initial stage of scanning the lower surface in step S2. The laser passes through the upper surface of the silicon carbide substrate and reflects on the lower surface of the silicon carbide substrate. The reflected signal is blocked by the defect. The four-quadrant detector only receives the reflected signal from the upper surface but cannot receive the reflected signal from the lower surface, forming a black defect morphology.

[0011] S3, using the laser detection instrument to emit laser, the laser is focused on the silicon carbide substrate body below the upper surface of the silicon carbide substrate for scanning, the laser emitter emits laser, irradiates on the silicon carbide substrate, the laser passes through the surface and the inside of the silicon carbide substrate and will be reflected, the four-quadrant detector collects the reflection signal and the reflection spot position signal, and analyzes the received signal, and then identifies the size and position of the micropipe defects M3 and M4 in the silicon carbide substrate body; wherein, the micropipe defects M3 and M4 are respectively located on the incident line and the reflection line of a certain laser light, M3 is the initial stage of the scanning of step S3, the laser passes through the upper surface of the silicon carbide substrate, and is reflected on the lower surface of the silicon carbide substrate, the reflection signal is blocked by the defect, the four-quadrant detector only receives the upper surface reflection signal but cannot receive the lower surface reflection signal, forming a black defect morphology, M4 is the end stage of the scanning of step S3, the laser passes through the upper surface of the silicon carbide substrate, and cannot be reflected on the lower surface due to being blocked by the defect, the four-quadrant detector only receives the upper surface reflection signal but cannot receive the lower surface reflection signal, forming a black defect morphology;

[0012] S4, connecting the defect morphologies M1 to M5 to form a morphology map of the micropipe defect and outputting it.

[0013] Furthermore, the thickness of the silicon carbide substrate to be inspected in S2 is greater than or equal to 60 micrometers.

[0014] Furthermore, the laser emitter in S2 emits a laser with a wavelength of 400-410 nm, which is irradiated onto the silicon carbide substrate.

[0015] Furthermore, the laser emitter in S2 emits a laser with a wavelength of 405 nm, which is irradiated onto the silicon carbide substrate.

[0016] Furthermore, the laser in S2 irradiates the silicon carbide substrate at an incident angle of 60-80°.

[0017] Furthermore, the laser in S2 irradiates the silicon carbide substrate at an incident angle of 70°.

[0018] Furthermore, in S3, the laser is focused on the inside of the silicon carbide substrate at a distance of 70-80 microns from the upper surface of the silicon carbide substrate for scanning.

[0019] Furthermore, in S3, the laser is focused on the inside of the silicon carbide substrate at a distance of 75 micrometers from the upper surface of the silicon carbide substrate for scanning.

[0020] Furthermore, in S4, the defect morphologies M1 to M5 are connected, and the morphology of the formed micropipe defect is V-shaped.

[0021] Beneficial effects: The detection method provided by the present invention can accurately obtain the total number and distribution of micropipe defects in the silicon carbide substrate, and distinguish the micropipe defects in the silicon carbide substrate from other defects. Similarly, it can also detect some internal inclusions that are difficult to detect on the surface.

[0022] In the detection method provided by the present invention, the laser will be reflected when passing through the surface and interior of the silicon carbide substrate. The detector collects the reflection signal and the reflection spot position signal (four-quadrant detector) and analyzes the received signal to identify the size and position of the defect, so as to replace the inspector's naked eye observation under a microscope. The detector collects the reflection signal and the reflection spot position signal as input, and outputs the number of micropipe defects and the position of the micropipe defects in the object to be detected. It can be seen that this method can automatically identify the defect position instead of manpower, saves time and manpower, and is not prone to errors, thereby improving the accuracy of the detection results and promoting the continuous improvement of silicon carbide substrates and epitaxial growth processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings will be briefly introduced below. Obviously, the accompanying drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0024] Figure 1 is a defect detection optical path diagram provided by embodiment 1 of the present invention;

[0025] Figure 2 This is an analysis diagram of a wafer scanned by a laser detection instrument provided in one embodiment 1 of the present invention;

[0026] Figure 3-1 This is a defect analysis diagram of a surface of a wafer scanned by a laser detection instrument provided in one embodiment 1 of the present invention;

[0027] Figure 3-2 This is an imaging analysis diagram of micropipe defect morphology on the wafer surface provided by Example 1 of the present invention;

[0028] Figure 4-1 It is a defect analysis diagram of a wafer body scanned by a laser detection instrument provided in one embodiment 1 of the present invention;

[0029] Figure 4-2 This is an imaging analysis diagram of micropipe defect morphology in a wafer provided by Example 1 of the present invention;

[0030] Figure 5-1 This is a defect analysis diagram of the lower surface of a wafer scanned by a laser detection instrument provided in one embodiment 1 of the present invention;

[0031] Figure 5-2 This is an imaging analysis diagram of micropipe defect morphology on the lower surface of a wafer provided by Example 1 of the present invention;

[0032] Figure 6-1 This is a total micro-pipe defect analysis diagram of a wafer scanned by a laser detection instrument provided in one embodiment 1 of the present invention;

[0033] Figure 6-2 This is a general wafer micropipe defect morphology imaging analysis diagram provided by Example 1 of the present invention;

[0034] Figure 7-1 It is an analysis diagram of total micro-pipe defects in a wafer actually scanned by a theoretical laser detection instrument provided in one embodiment 1 of the present invention;

[0035] Figure 7-2 This is a morphology image obtained by scanning a micro-pipe defect with a laser detection instrument in theory according to an embodiment 1 of the present invention;

[0036] Figure 8-1 It is one of the topographic images obtained by scanning micro-pipe defects using an actual laser detection instrument provided in one embodiment 1 of the present invention;

[0037] Figure 8-2 This is the second morphological image obtained by scanning micro-pipe defects using an actual laser detection instrument provided in Example 1 of the present invention;

[0038] Fig. 9 This is a topographic image obtained by scanning a micro-pipe defect using an actual laser detection instrument provided in Example 2 of the present invention;

[0039] Fig.10 This is a morphology image obtained by scanning small particles and other defects using an actual laser detection instrument provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. In the embodiment, if no specific technology or conditions are indicated, the technology or conditions described in the document in this area or the product specification are carried out. If the manufacturer is not indicated for reagents used or instruments, they are all conventional products that can be obtained commercially.

[0041] Example 1

[0042] The surface defects of silicon carbide substrates are detected by laser detection instruments, which should have the following conditions: a) laser light source, 405nm laser transmitter, polarizer; b) reflection imaging detector, four-quadrant detector; c) vacuum and cooling system, sample rotating rack, track system for moving light source, etc.; d) thickness detector, image acquisition equipment and image analysis system, surface defect distribution map. Generally, commercially available laser detection instruments have the above components. If a component is missing, the corresponding component module can be purchased and assembled, and the assembly method is the existing conventional connection method.

[0043] Specifically, the polarizer is connected to the laser emitter, and the laser generated by the laser emitter passes through the polarizer at a certain incident angle to irradiate the silicon carbide substrate placed on the horizontal carrier. The silicon carbide substrate is vacuum-adsorbed and tightly attached to the carrier. The carrier rotates at high speed driven by the sample rotating frame, and the laser beam moves from the outside to the inside, scanning the entire silicon carbide substrate. The reflected laser beam signal is collected by detectors such as reflection imaging detectors and four-quadrant detectors. After the information is collected, the system performs image analysis to form surface defect distribution maps and various defect morphology maps.

[0044] In a specific embodiment, when the laser detection instrument scans the silicon carbide substrate, the laser emitter emits a laser with a wavelength of 405nm, which is irradiated on the silicon carbide substrate at an incident angle of 70°. The laser passes through the surface and interior of the silicon carbide substrate and is reflected. The detector (i.e., the four-quadrant detector) collects the reflection signal and the reflection spot position signal, and analyzes the received signal to identify the size and position of the defect. The defect detection optical path diagram is shown in FIG. Figure 1 .

[0045] Take the silicon carbide substrate to be tested, use the laser beam generated by the surface defect inspection system (i.e., image acquisition equipment and image analysis system) to perform a frontal scan on the surface and body of the silicon carbide substrate to be tested, and collect and determine the signal intensity and position of the reflected light from the surface and body to obtain the total number and distribution of micropipe defects in the silicon carbide substrate. In general, for the detected micropipe defects, the laser detection instrument will scan the silicon carbide substrate twice:

[0046] ①. The laser is focused on the surface of the silicon carbide substrate for scanning for the first time. The laser will be reflected when passing through the surface and interior of the silicon carbide substrate. The detector (four-quadrant detector) collects the reflection signal and the reflection spot position signal and analyzes the received signal to identify the size and position of the micropipe defect;

[0047] ②. The second laser is focused on the inside of the silicon carbide substrate 75μm away from the surface of the silicon carbide substrate for scanning. The laser will be reflected when passing through the surface and interior of the silicon carbide substrate. The detector (four-quadrant detector) collects the reflection signal and the reflection spot position signal and analyzes the received signal to identify the size and position of the micropipe defect.

[0048] Combined with the analysis of the signals received after two scans, it is found that the imaging morphology of micropipe defects is significantly different from that of other defects, which can accurately detect micropipe defects in silicon carbide substrates and distinguish micropipe defects from other defects in silicon carbide substrates.

[0049] The detection principle of the present invention is described below, including:

[0050] Laser detection instrument detects micro-pipe defect imaging principle: Micro-pipe defects run through the entire chip, and can be regarded as micro-pipe defects with the following three states of defect morphology: ①. The defect is on the upper surface of the chip; ②. The defect is in the body of the chip; ③. The defect is on the lower surface of the chip. Therefore, the defect morphology of the three states can be analyzed first, and finally combined to obtain the micro-pipe defect morphology. Laser detection instrument scanning chip analysis diagram see Figure 2 .Note: Figure 2 The L0 stage is considered as the background stage. No defects have been scanned yet. The reflected light from the upper and lower surfaces of the wafer are received by the detector and no morphology can be formed.

[0051] When the defect is on the upper surface of the wafer and is scanned by the laser detection instrument: ①. The L1 stage is regarded as the initial stage of scanning the defect. The laser passes through the upper surface of the wafer and reflects on the lower surface of the wafer. The reflected signal is blocked by the defect. The detector only receives the reflected signal from the upper surface but cannot receive the reflected signal from the lower surface, forming a black defect morphology (M1); ②. The L2 stage is regarded as the end stage of scanning the defect. The laser scans the defect on the upper surface of the wafer, and the detector cannot receive any signal, forming a black defect morphology (M2) (theoretically, the color of morphology M2 will generally be darker than morphology M1, and the signal will be stronger). See the analysis diagram of the defect on the upper surface of the wafer scanned by the laser detection instrument. Figure 3-1 , microtubule defect morphology imaging analysis diagram is shown in Figure 3-2 .

[0052] When the defect is inside the wafer and is scanned by the laser detection instrument: ①. The L1 stage is regarded as the initial stage of scanning the defect. The laser passes through the upper surface of the wafer and is reflected on the lower surface of the wafer. The reflected signal is blocked by the defect. The detector only receives the reflected signal from the upper surface but not from the lower surface, forming a black defect morphology (M3); ②. The L2 stage is regarded as the end stage of scanning the defect. The laser passes through the upper surface of the wafer and is blocked by the defect and cannot be reflected on the lower surface. The detector only receives the reflected signal from the upper surface but not from the lower surface, forming a black defect morphology (M4) (In theory, the color of morphology M3 is generally the same as that of morphology M4, and the signal is also the same). See the analysis diagram of defects inside the wafer scanned by the laser detection instrument. Figure 4-1 , microtubule defect morphology imaging analysis diagram is shown in Figure 4-2 .

[0053] When the defect is on the lower surface of the wafer and is scanned by a laser detection instrument: ①. The L1 stage is regarded as the initial stage of scanning the defect. The laser passes through the upper surface of the wafer and is reflected on the lower surface of the wafer. The reflected signal is blocked by the defect. The detector only receives the reflected signal from the upper surface but not from the lower surface, forming a black defect morphology (M5); ②. Since the defect is on the lower surface of the wafer, there is no laser reflection on the lower surface of the wafer, so there is no L2 stage (theoretically, the color of morphology M5 is generally the same as morphology M3 and M4, and the signal is also the same). See the defect analysis diagram of the lower surface of the wafer scanned by the laser detection instrument. Figure 5-1 , microtubule defect morphology imaging analysis diagram is shown in Figure 5-2 .

[0054] Micropipe defects in the wafer penetrate the wafer. It can be roughly considered that the micropipe defects are not only on the upper surface of the wafer, but also on the lower surface of the wafer and in the wafer body. Therefore, the defect morphology M1 to M5 are connected together, which can be roughly considered as the defect morphology obtained after the laser detection instrument scans the micropipe defects. The analysis diagram of micropipe defects in the wafer scanned by the laser detection instrument is shown in Figure 6-1 , microtubule defect morphology imaging analysis diagram is shown in Figure 6-2 .

[0055] Micropipe defects penetrate the wafer. After laser scanning of micropipe defects, after L0, L1, and L2 stages, the final micropipe defect morphology (seagull-shaped, V-shaped) can be obtained. The analysis diagram is different from the actual micropipe defect morphology scanned by the laser detection instrument. Figure 1 The laser detection instrument scans the micro-pipe defect analysis diagram in the wafer. Figure 7-1 , microtubule defect morphology imaging analysis diagram is shown in Figure 7-2 , the actual laser detection instrument scans the micro-pipe defect morphology. Figure 8-1 and Figure 8-2 .

[0056] Through the above process, the number and location of micropipe defects in the silicon carbide substrate to be tested can be identified, thereby achieving the purpose of automatic detection. It can replace manual identification, save time and manpower, and is less prone to errors, thereby improving the accuracy of the detection results and promoting the continuous improvement of silicon carbide substrates and epitaxial growth processes.

[0057] Example 2

[0058] Referring to the method in Example 1, another silicon carbide substrate to be tested is placed on the carrier of the laser detection instrument, and identification parameters such as substrate information are input. After selecting the appropriate recipe, the instrument starts to automatically scan the substrate for detection. When the laser detection instrument scans the silicon carbide substrate, the laser emitter emits a laser with a wavelength of 410nm, irradiates the silicon carbide substrate at an incident angle of 60°, and focuses on the upper surface, lower surface and body of the silicon carbide substrate for scanning, wherein the body scanning is to focus the laser on the body of the silicon carbide substrate 70μm away from the upper surface of the silicon carbide substrate for scanning.

[0059] After the test is completed, you can get Fig. 9 The detection image shown, Fig. 9 For microtubule detection images, additional detection methods can be added to further differentiate them.

[0060] Example 3

[0061] Referring to the method in Example 1, another silicon carbide substrate to be tested is placed on the carrier of the laser detection instrument, and identification parameters such as substrate information are input. After selecting the appropriate recipe, the instrument starts to automatically scan the substrate for detection. When the laser detection instrument scans the silicon carbide substrate, the laser emitter emits a laser with a wavelength of 400nm, irradiates the silicon carbide substrate at an incident angle of 80°, and focuses on the upper surface, lower surface and body of the silicon carbide substrate for scanning, wherein the body scanning is to focus the laser on the body of the silicon carbide substrate 80μm away from the upper surface of the silicon carbide substrate for scanning.

[0062] After the test is completed, you can get Fig.10 The detection image shown. Fig.10 For defect detection images such as small particles, pits, or internal inclusions (mainly internal inclusion defects), additional detection means can be added to further distinguish them.

[0063] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0064] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0065] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for detecting micropipe defects in a silicon carbide substrate, characterized in that: The following steps are involved: S1, prepare a laser detection instrument, the laser detection instrument comprising: a) a laser emitter and a polarizer; b) a reflection imaging detector and a four-quadrant detector; c) a vacuum system and a cooling system, a sample rotation system and a track system for moving the light source; d) a thickness detector, an image acquisition device and an image analysis system, wherein the image analysis system performs analysis and outputs a surface defect distribution map; The polarizer is connected to the laser emitter, so that the laser generated by the laser emitter passes through the polarizer and irradiates the silicon carbide substrate placed on the horizontal carrier at a certain incident angle; the laser beam signal reflected by the silicon carbide substrate is collected by the reflection imaging detector and the four-quadrant detector, and after the information is collected, it is sent to the image analysis system, and the image analysis system combines the detection results of the thickness detector and the image acquisition device to perform image analysis to form a surface defect distribution map; S2, take the silicon carbide substrate to be inspected, place it on the sample rotation system, use the laser detection instrument to emit laser, focus on the upper surface and lower surface of the silicon carbide substrate for scanning, the laser emitter emits laser, irradiates the silicon carbide substrate, the laser passes through the surface and the inside of the silicon carbide substrate and will be reflected, the four-quadrant detector collects the reflection signal and the reflection spot position signal, and analyzes the received signal, and then identifies the size and position of the upper surface micropipe defects M1 and M2 on the bottom surface of the silicon carbide substrate, and the size and position of the micropipe defect M5 on the lower surface; wherein the micropipe defects M1 and M2 are respectively located on the incident line and the reflection line of a certain laser light, M1 is the initial stage of scanning the upper surface in step S2, and the laser The laser passes through the upper surface of the silicon carbide substrate and reflects on the lower surface of the silicon carbide substrate. The reflected signal is blocked by the defect. The four-quadrant detector only receives the reflected signal from the upper surface but cannot receive the reflected signal from the lower surface, forming a black defect morphology. M2 is the end stage of scanning the upper surface in step S2. The laser scans a defect on the upper surface of the silicon carbide substrate, and the four-quadrant detector cannot receive any signal, forming a black defect morphology. M5 is the initial stage of scanning the lower surface in step S2. The laser passes through the upper surface of the silicon carbide substrate and reflects on the lower surface of the silicon carbide substrate. The reflected signal is blocked by the defect. The four-quadrant detector only receives the reflected signal from the upper surface but cannot receive the reflected signal from the lower surface, forming a black defect morphology. S3, using the laser detection instrument to emit laser, the laser is focused on the silicon carbide substrate body below the upper surface of the silicon carbide substrate for scanning, the laser emitter emits laser, irradiates on the silicon carbide substrate, the laser passes through the surface and the inside of the silicon carbide substrate and will be reflected, the four-quadrant detector collects the reflection signal and the reflection spot position signal, and analyzes the received signal, and then identifies the size and position of the micropipe defects M3 and M4 in the silicon carbide substrate body; wherein, the micropipe defects M3 and M4 are respectively located on the incident line and the reflection line of a certain laser light, M3 is the initial stage of the scanning of step S3, the laser passes through the upper surface of the silicon carbide substrate, and is reflected on the lower surface of the silicon carbide substrate, the reflection signal is blocked by the defect, the four-quadrant detector only receives the upper surface reflection signal but cannot receive the lower surface reflection signal, forming a black defect morphology, M4 is the end stage of the scanning of step S3, the laser passes through the upper surface of the silicon carbide substrate, and cannot be reflected on the lower surface due to being blocked by the defect, the four-quadrant detector only receives the upper surface reflection signal but cannot receive the lower surface reflection signal, forming a black defect morphology; S4, connecting the defect morphologies M1 to M5 to form a morphology map of the micropipe defect and outputting it.

2. The method for detecting micropipe defects in a silicon carbide substrate according to claim 1, characterized in that: The thickness of the silicon carbide substrate to be inspected in S2 is greater than or equal to 60 micrometers.

3. The method for detecting micropipe defects in a silicon carbide substrate according to claim 1, characterized in that: The laser emitter in S2 emits a laser with a wavelength of 400-410 nm, which irradiates the silicon carbide substrate.

4. The method for detecting micropipe defects in a silicon carbide substrate according to claim 3, characterized in that: The laser emitter in S2 emits a laser with a wavelength of 405 nm, which irradiates the silicon carbide substrate.

5. The method for detecting micropipe defects in a silicon carbide substrate according to any one of claims 2 to 4, characterized in that: The laser in S2 irradiates the silicon carbide substrate at an incident angle of 60-80°.

6. The method for detecting micropipe defects in a silicon carbide substrate according to claim 5, characterized in that: The laser in S2 irradiates the silicon carbide substrate at an incident angle of 70°.

7. The method for detecting micropipe defects in a silicon carbide substrate according to claim 2, characterized in that: In S3, the laser is focused within the silicon carbide substrate body at a distance of 70-80 microns from the upper surface of the silicon carbide substrate for scanning.

8. The method for detecting micropipe defects in a silicon carbide substrate according to claim 7, characterized in that: In S3, the laser is focused within the silicon carbide substrate body at a distance of 75 microns from the upper surface of the silicon carbide substrate for scanning.

9. The method for detecting micropipe defects in a silicon carbide substrate according to any one of claims 6 to 8, characterized in that: In S4, the defect morphologies M1 to M5 are connected, and the morphology of the micropipe defect formed is V-shaped.

Images