Defect visual inspection device for silicon carbide epitaxial wafer
By designing a combination of a wafer stage, positioning components, and lighting components, the problems of low accuracy and cumbersome operation in existing silicon carbide epitaxial wafer defect detection have been solved, achieving high-precision visual defect inspection, reducing mercury residue, and improving the yield of silicon carbide epitaxial wafers.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2026-03-20
AI Technical Summary
Existing manual visual inspection devices suffer from low accuracy, large human error, and cumbersome operation in the detection of defects in silicon carbide epitaxial wafers.
A defect visual inspection device was designed, comprising a wafer stage, a positioning component, a rotating component, and an illumination component. By rotating the wafer stage and accurately positioning the wafers, the device eliminates the placement deviation of the wafers on the wafer stage. Combined with the shape change of the rotating component and the auxiliary illumination of the illumination component, high-precision defect detection is achieved.
It improves the accuracy and convenience of visual inspection of defects in silicon carbide epitaxial wafers, ensures that there are no defects on the test path, reduces mercury residue, and improves the yield.
Smart Images
Figure CN224019674U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of silicon carbide epitaxial wafer detection, and in particular to a defect visual inspection device for silicon carbide epitaxial wafer. BACKGROUND
[0002] Silicon carbide (SiC) epitaxial material is the key to realize device manufacturing, and the main technical indicators include epitaxial layer thickness, lattice layout, material structure, morphology, physical properties, surface roughness and doping concentration, etc. For doping concentration detection, a mercury probe CV tester is mainly used, which uses Schottky barrier capacitance C-V characteristics to test the doping concentration. However, surface morphology defects such as scratches, triangular defects, carrot defects, downfalls and particles often occur on SiC epitaxial wafers, which will affect the carrier concentration test (referred to as CV test) of the mercury probe CV tester on SiC epitaxial wafers. Generally speaking, when the mercury drop touches the defect, mercury residue will appear on the wafer (which can be regarded as an alias of SiC epitaxial wafer), which is difficult to clean thoroughly and affects the yield. Before the CV test of the SiC epitaxial wafer, it is necessary to ensure that there is no defect on the test point as much as possible, so it is necessary to detect the defect (which can be understood as defect visual inspection).
[0003] The existing manual visual inspection device can be seen from Figure 1 , a "+" or "×" green tape is pasted on the single wafer box as a mark line (which can be regarded as a test path), and then two positioning edge positions are drawn at the bottom to observe the defects of the wafer on the test path. Secondly, as shown in Figure 2 , the technician uses a suction pen to suck the wafer and place it on a mold, and uses a strong light flashlight to observe whether there is a defect on the wafer on the test path. However, the existing manual visual inspection device has a test deviation caused by human operation, resulting in low precision of defect visual inspection. Practical new type content
[0004] The present application provides a defect visual inspection device for silicon carbide epitaxial wafer, which aims to improve the precision of defect visual inspection of silicon carbide epitaxial wafer.
[0005] In order to achieve the above purpose, the present application provides the following technical solutions:
[0006] A defect visual inspection device for silicon carbide epitaxial wafer, comprising:
[0007] A wafer stage for placing a wafer and rotating the wafer;
[0008] A positioning component for fixing the placement position of the wafer, the positioning component being arranged on the table surface of the wafer stage;
[0009] A rotating component for mounting and rotating the testing component, the rotating component is arranged on the back of the wafer stage; the testing component is a reference for wafer defect detection;
[0010] A fixed support for mounting the wafer stage, the fixed support is also provided with a lighting component, and the mounting position of the lighting component is above the wafer stage.
[0011] Optionally, the wafer stage is electrically connected with a first driving mechanism, the first driving mechanism is used for driving the wafer stage to rotate to a corresponding angle in response to a first signal issued by a controller.
[0012] Optionally, the positioning component comprises a first annular structure provided with a gap; the gap is used for providing a moving space for a suction pen, the suction pen is used for picking and placing the wafer; the inner diameter of the first annular structure is consistent with the diameter of the wafer.
[0013] Optionally, the rotating component is electrically connected with a second driving mechanism, the second driving mechanism is used for driving the rotating component to rotate to a corresponding angle in response to a second signal issued by a controller.
[0014] Optionally, the testing component comprises a testing path provided with a testing point, the width of the testing path is consistent with the width of a probe, and the area of the testing point is consistent with the area of the probe, the probe is used for testing the carrier concentration of the wafer.
[0015] Optionally, when the testing component rotates from a first angle to a second angle following the rotating component, the testing path changes from a first shape to a second shape.
[0016] Optionally, the wafer stage comprises a second annular structure, the inner diameter of the second annular structure is smaller than the diameter of the wafer.
[0017] Optionally, the lighting component comprises a strong light lamp, the strong light lamp is parallel to the table surface of the wafer stage, and the distance between the strong light lamp and the table surface is 5-15 cm.
[0018] Optionally, the rotating component comprises a third annular structure, the inner diameter of the third annular structure is greater than or equal to the diameter of the wafer.
[0019] Optionally, the outer diameters of the wafer stage, the positioning component and the rotating component are consistent.
[0020] The defect visual inspection device of the silicon carbide epitaxial wafer provided by the application comprises: a wafer stage for placing a wafer and rotating the wafer, a positioning component for fixing the placement position of the wafer, the positioning component being arranged on the table surface of the wafer stage, a rotating component for mounting a test component and rotating the test component, the rotating component being arranged on the back surface of the wafer stage, the test component being a reference for wafer defect detection, a fixing support for mounting the wafer stage, and an illumination component mounted on the fixing support and located above the wafer stage. The positioning component is used to accurately position the wafer on the wafer stage, eliminate the deviation of the placement position of the wafer on the wafer stage, assist the user in accurately observing the defects on the wafer, and change the position of the wafer or the shape of the test path according to the detection requirement, so as to ensure that the position of the wafer can avoid detecting defects, and the user's annoyance caused by holding the illumination is solved, thereby effectively improving the accuracy and convenience of defect visual inspection. BRIEF DESCRIPTION OF DRAWINGS
[0021] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.
[0022] Figure 1 A structure schematic diagram of an existing manual visual inspection device provided by the embodiment of the application;
[0023] Figure 2 A wafer taking schematic diagram of an existing manual visual inspection device provided by the embodiment of the application;
[0024] Figure 3 A structure schematic diagram of a defect visual inspection device of a silicon carbide epitaxial wafer provided by the embodiment of the application;
[0025] Figure 4 A structure schematic diagram of a wafer stage provided by the embodiment of the application;
[0026] Figure 5 A structure schematic diagram of a positioning component provided by the embodiment of the application;
[0027] Figure 6 A structure schematic diagram of a test component provided by the embodiment of the application;
[0028] Figure 7 A structure schematic diagram of a rotating component provided by the embodiment of the application;
[0029] Figure 8 A schematic diagram of a combination structure provided by the embodiment of the application;
[0030] Wherein, the slide stage 1, the positioning component 2, the rotating component 3, the testing component 4, the fixed support 5, the lighting component 6, the second ring structure 11, the first ring structure 21, the notch 22, the suction pen 23, the testing path 41, the testing point 42, the third ring structure 31. DETAILED DESCRIPTION
[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.
[0032] In the present application, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between the entities or operations. The terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or equipment including the element.
[0033] Based on the existing artificial inspection device mentioned in the background, the applicant found through use that the existing device mainly has the following problems: (1) the existing device does not have accurate wafer positioning function, which is easy to cause deviation between the placement position of the lens on the stage and the test path of the mercury probe, and it is difficult to accurately inspect whether there is a defect on the test path; (2) the existing device does not have the function of controlling the wafer rotation to avoid defects, when there is a certain number of defects on the test path, only when the wafer is placed on the stage, the wafer can be manually rotated by a certain angle, but it still cannot guarantee that the placement position of the wafer on the stage can avoid detecting defects; (3) when using the existing device, a strong light flashlight needs to be held by hand, making the inspection process more tedious and time-consuming.
[0034] In view of the above findings of the applicant, the embodiments of the present application provide a defect inspection device for silicon carbide epitaxial wafer, to ensure that during the process of testing the carrier concentration of SiC epitaxial wafer by mercury probe CV, mercury residue on SiC epitaxial wafer caused by defects on the test path of the mercury probe can be more accurately eliminated.
[0035] AsFigure 3 As shown in the figure, a structural schematic diagram of a defect visual inspection device of a silicon carbide epitaxial wafer provided by an embodiment of the present application, comprising the following components.
[0036] A wafer stage 1 for placing and rotating the wafer.
[0037] Optionally, referring to Figure 4 As shown in the figure, the wafer stage 1 comprises a second ring structure 11, and the inner diameter of the second ring structure 11 is smaller than the diameter of the wafer. The wafer supporting ring width of the second ring structure 11 (which can be understood as the size of the overlapping area of the wafer and the second ring structure 11, or the size of the supporting area on the table surface of the wafer stage 1 for placing the wafer) is smaller than the edge removal distance of the wafer test, so as to ensure that the wafer can be placed flat on the second ring structure 11.
[0038] In possible embodiments, the edge removal distance generally refers to the gap distance between the grains in the wafer processing process, which can also be called a scribe line or a street.
[0039] In possible embodiments, the ring width of the second ring structure 11 can be set to 3mm, and the outer diameter and thickness of the second ring structure 11 can be set by the technician according to the actual situation.
[0040] Optionally, the wafer stage 1 is electrically connected with a first driving mechanism, and the first driving mechanism is used to drive the wafer stage 1 to rotate the wafer to a corresponding angle in response to a first signal issued by a controller.
[0041] In possible embodiments, the first driving mechanism comprises a driving motor, and the controller comprises but is not limited to a computer.
[0042] In possible embodiments, the technician can set the rotation angle of the wafer stage 1 in the controller (or the control software of the computer), so that the controller issues the first signal to drive the wafer stage 1 to rotate to the rotation angle.
[0043] It can be understood that by controlling the wafer stage 1 to rotate to the corresponding angle, the wafer is rotated to the corresponding angle, so as to facilitate accurate avoidance of defects in the wafer defect visual inspection process.
[0044] In possible embodiments, the table surface of the wafer stage 1 is parallel to the ground.
[0045] A positioning component 2 for fixing the placement position of the wafer, which is arranged on the table surface of the wafer stage 1.
[0046] Optionally, referring to Figure 5As shown, the positioning component 2 comprises a first annular structure 21 provided with a gap 22, the gap 22 is used to provide a moving space for a suction pen 23 used for taking and placing the wafer, and the inner diameter of the first annular structure 21 is consistent with the diameter of the wafer.
[0047] It can be understood that the gap 22 on the first annular structure 21 can be regarded as a suction pen moving area when taking and placing the wafer, so as to ensure that the actual test area of the wafer is perfectly matched with the test point 42 shown in the test component 4.
[0048] In possible implementation manners, the outer circle size (which can be regarded as the outer diameter), ring width and thickness of the first annular structure 21 can be set by the technician according to the actual situation.
[0049] The rotating component 3 is used for installing and driving the test component 4 to rotate, the rotating component 3 is arranged on the back of the wafer stage 1, and the test component 4 is a reference for wafer defect detection.
[0050] Optionally, referring to Figure 6 As shown, the test component 4 comprises a test path 41 provided with a test point 42, the width of the test path 41 is consistent with the width of the probe, and the area of the test point 42 is consistent with the area of the probe, and the probe is used to test the carrier concentration of the wafer.
[0051] Optionally, the rotating component 3 is electrically connected with the second driving mechanism, and the second driving mechanism is used to drive the rotating component 3 to rotate to a corresponding angle in response to a second signal issued by the controller.
[0052] In possible implementation manners, the second driving mechanism comprises a driving motor, and the controller comprises but is not limited to a computer.
[0053] Optionally, when the test component 4 rotates from a first angle to a second angle following the rotating component 3, the test path 41 changes from a first shape to a second shape.
[0054] In possible implementation manners, the first shape can be set as a "+" shape, and the second shape can be set as a "×" shape.
[0055] In possible implementation manners, the technician can set the rotating angle of the rotating component 3 in the controller (or the control software of the computer), so that the controller issues the second signal to drive the rotating component 3 to rotate to the rotating angle.
[0056] It can be understood that by controlling the rotating component 3 to rotate to a corresponding angle, the test component 4 is rotated to the corresponding angle, so as to realize the conversion of the test path 41 with different shapes.
[0057] Optionally, referring to Figure 7As shown, the rotating component 3 comprises a third annular structure 31, and the inner diameter of the third annular structure 31 is greater than or equal to the diameter of the wafer.
[0058] In some examples, the outer diameter and the thickness of the third annular structure 31 can be set by the technician according to the actual situation.
[0059] It can be understood that, since the inner circle of the second annular structure 11 and the third annular structure 31 is hollow, the line of sight can be directly and clearly observed whether there is a defect on the wafer on the test path 41 and the test point 42 during the wafer defect visual inspection.
[0060] The fixing support 5 for mounting the wafer stage 1 is also provided with the lighting component 6, and the installation position of the lighting component 6 is above the wafer stage 1.
[0061] Optionally, the lighting component 6 comprises a strong light lamp, and the strong light lamp is parallel to the table surface of the wafer stage 1, and the distance between the strong light lamp and the table surface is 5-15 cm.
[0062] It can be understood that, the distance between the strong light lamp and the table surface can be adjusted by the technician according to the actual situation, so as to ensure that the light of the strong light lamp can irradiate the entire wafer.
[0063] In possible embodiments, the installation position of the wafer stage 1 on the fixing support 5 can be set by the technician according to the actual situation.
[0064] Optionally, the outer diameters of the wafer stage 1, the positioning component 2 and the rotating component 3 are consistent.
[0065] In some examples, the combined structure of the wafer stage 1, the positioning component 2 and the rotating component 3 can be seen from Figure 8 as shown.
[0066] It can be understood that, the outer diameters of the wafer stage 1, the positioning component 2 and the rotating component 3 are consistent, which can make the installation and adaptation work between the wafer stage 1, the positioning component 2 and the rotating component 3 more simple.
[0067] In some examples, the use steps of the defect inspection device for silicon carbide epitaxial wafer shown in the embodiments of the present application can be: (1) using a suction pen to adsorb the wafer, and placing the wafer on the table surface of the wafer table according to the guidance of the positioning component; (2) triggering the rotation component to rotate to a corresponding angle (for example, 0° or 45°) according to the test requirements, so as to determine a test path of a corresponding shape; (3) starting the illumination component to illuminate, so as to facilitate the observation of defects on the wafer, and triggering the wafer table to rotate to a corresponding angle (for example, 0°-45°) during the observation, so as to ensure that there is no defect on the wafer at the test point; (4) when the defect inspection is completed, according to the wafer placement position shown by the positioning component, using the suction pen to take away the wafer on the wafer table and transfer it to the CV test table for carrier concentration test.
[0068] The above-mentioned structure uses the positioning component to realize the accurate positioning of the wafer on the wafer table, eliminates the deviation of the placement position of the wafer on the wafer table, assists the user to accurately observe the defects on the wafer, can change the position of the wafer or the shape of the test path according to the detection requirements, ensures that the position of the wafer can avoid detecting defects, and can also solve the annoyance caused by the user holding the illumination, thereby effectively improving the accuracy and convenience of defect inspection.
[0069] Although the above discussion contains a number of specific implementation details, these should not be construed as limiting the scope of the present application. Certain features described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented separately or in any suitable subcombination.
[0070] The above description is merely the preferred embodiments and the explanation of the technical principles of the present application. It should be understood by those skilled in the art that the disclosed scope of the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and also covers other technical solutions formed by the combinations of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the above technical features are replaced with the technical features disclosed in the present application (but not limited to) having similar functions to form technical solutions.
Claims
1. A defect inspection device for silicon carbide epitaxial wafers, characterized in that, include: A wafer stage for placing and rotating wafers; A positioning component for fixing the placement position of the wafer, the positioning component being disposed on the stage surface of the wafer carrier; A rotating component for mounting and rotating a test component, the rotating component being disposed on the back side of the wafer stage; the test component serving as a reference object for wafer defect detection; A mounting bracket for mounting the slide stage is provided, and an illumination component is also mounted on the mounting bracket, with the illumination component positioned above the slide stage.
2. The apparatus according to claim 1, characterized in that, The wafer stage is electrically connected to the first drive mechanism, which is used to drive the wafer stage to rotate to the corresponding angle in response to a first signal issued by the controller.
3. The apparatus according to claim 1, characterized in that, The positioning component includes a first annular structure with a pre-set notch; the notch is used to provide movement space for the suction pen, which is used to pick up and place the wafer; the inner diameter of the first annular structure is the same as the diameter of the wafer.
4. The apparatus according to claim 1, characterized in that, The rotating component is electrically connected to the second drive mechanism, which is used to drive the rotating component to rotate to the corresponding angle in response to a second signal issued by the controller.
5. The apparatus according to claim 1, characterized in that, The test component includes a test path with preset test points. The width of the test path is the same as the width of the probe, and the area of the test point is the same as the area of the probe. The probe is used to test the carrier concentration of the wafer.
6. The apparatus according to claim 5, characterized in that, When the test component rotates from a first angle to a second angle following the rotation of the rotating component, the test path changes from a first shape to a second shape.
7. The apparatus according to claim 1, characterized in that, The wafer stage includes a second annular structure, the inner diameter of which is smaller than the diameter of the wafer.
8. The apparatus according to claim 1, characterized in that, The lighting component includes a high-intensity lamp, which is parallel to the surface of the slide stage, and the distance between the high-intensity lamp and the surface is 5-15cm.
9. The apparatus according to claim 1, characterized in that, The rotating component includes a third annular structure, the inner diameter of which is greater than or equal to the diameter of the wafer.
10. The apparatus according to claim 1, characterized in that, The outer diameters of the slide stage, the positioning component, and the rotating component are the same.