Silicon wafer subfissure detection device based on photoluminescence

Abstract

The utility model relates to a photoluminescence-based silicon wafer subfissure detection device, which comprises a conveying streamline, a laser excitation mechanism and an infrared camera mechanism, the laser excitation mechanism comprises a mounting bracket and a laser excitation assembly mounted on the mounting bracket, and the infrared camera mechanism is mounted on the mounting bracket and positioned above the laser excitation assembly; the two ends of the laser excitation assembly are rotationally connected with the mounting support through light source fixing arms. The laser excitation assembly is rotationally connected with the mounting bracket through a light source fixing arm, so that a laser light source on the laser excitation assembly can swing around an X axis to adjust a light source illumination angle, and the light source adjustment only has one adjustment variable to simplify the imaging adjustment work; meanwhile, based on the photoluminescence principle, the laser excitation assembly emits laser with specific wavelength to serve as an excitation light source, the infrared camera mechanism carries out light sensing and imaging, whether the sample wafer has the hidden crack defect or not is judged, imaging is easier, and defect parameter detection is reliable and accurate.

Description

Technical Field

[0001] The utility model relates to the technical field of silicon wafer sorting equipment, and particularly relates to a device for detecting hidden cracks of silicon wafers based on photoluminescence. Background Art

[0002] As an important raw material for solar cells, silicon wafers are widely used in the production and manufacturing of products such as solar cells and circuit boards. In the production process of silicon wafers, as the terminal equipment for quality control, a silicon wafer sorter detects and sorts the quality grades of silicon wafers in terms of size, dirt, hidden cracks, holes, resistivity, etc., to ensure the quality of products such as solar cells and circuit boards made of silicon wafers. Among them, for the detection of hidden cracks on silicon wafers, due to the crystal structure characteristics, silicon wafers are extremely prone to cracking during the processes of crystal pulling, cutting, and cleaning, generating visible cracks and invisible hidden cracks. The hidden cracks of silicon wafers will directly affect the performance of photovoltaic modules.

[0003] Patent CN210571994U discloses a defect detection device, which includes: a detection unit, arranged on the frame of the conveying device and located above the designated detection position of the conveying device, for detecting hidden cracks of battery wafers or silicon wafers passing through the designated detection position; a light source, arranged on the frame of the conveying device, for providing light to the designated detection position; a reflector, arranged at the interval position and lower than the conveying plane of the conveying device; a light blocking plate, which is used to block external light from irradiating to the designated detection position, and the light blocking plate is vertically arranged between the light source and the conveying plane of the conveying device; an angle adjustment mechanism, for adjusting the illumination angle of the light source; a height adjustment mechanism, for adjusting the height of the light source. This patent can automatically detect the hidden crack defects of battery wafers or silicon wafers during the transmission process, but this device has too many adjustment variables for the light source, and the adjustment of each variable is not convenient, resulting in complicated installation and debugging, long debugging time, difficult control of the consistency between machines, and high costs. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a device for detecting hidden cracks of silicon wafers based on photoluminescence, which can achieve fewer light source adjustment variables and simpler imaging to solve the problems proposed in the above background art.

[0005] To achieve the above object, the present utility model provides the following technical solutions: A device for detecting hidden cracks in silicon wafers based on photoluminescence, comprising a conveying streamline, a laser excitation mechanism, and an infrared camera mechanism. The laser excitation mechanism includes a mounting bracket and a laser excitation component mounted on the mounting bracket. The two sides of the mounting bracket are respectively mounted on the two sides of the conveying streamline. The infrared camera mechanism is mounted on the mounting bracket and is located above the laser excitation component. Both ends of the laser excitation component are rotatably connected to the mounting bracket through light source fixing arms.

[0006] Further, arc grooves are provided on both sides of the mounting bracket. One end of the light source fixing arm is provided with a positioning post, and the positioning post passes through the arc groove and slides in the arc groove.

[0007] Further, the conveying streamline includes a first conveying component and a second conveying component arranged in sequence along the silicon wafer conveying direction. There is a gap between the output end of the first conveying component and the input end of the second conveying component. The mounting bracket is located directly above the gap, and the laser excitation component is mounted on one side of the gap.

[0008] Further, a baffle is mounted on the mounting bracket and is located directly above the gap.

[0009] Further, a background board is mounted on the mounting bracket and is located directly below the gap.

[0010] Further, the camera mechanism includes an infrared camera and a camera adjustment component, and the infrared camera is mounted on the camera adjustment component.

[0011] Further, the camera adjustment component includes a Z-direction adjustment structure, a Y-direction adjustment structure, and an X-direction adjustment structure. The Y-direction adjustment structure is mounted on the Z-direction adjustment structure, and the X-direction adjustment structure is mounted on the Y-direction adjustment structure.

[0012] Further, the Z-direction adjustment structure includes a Z-direction fixing plate, a Z-direction screw, a Z-direction adjustment frame, and a Z-direction adjustment seat. The Z-direction screw passes through the upper end and the lower end of the Z-direction adjustment frame and is rotatably connected to the Z-direction adjustment frame. The Z-direction adjustment seat is connected to the Z-direction screw, and the Z-direction fixing plate is mounted on the Z-direction adjustment seat.

[0013] Further, the Y-direction adjustment structure includes a Y-direction adjustment seat, a Y-direction adjustment screw, and a Y-direction adjustment frame. The Y-direction adjustment frame is mounted on the Z-direction fixing plate. The Y-direction adjustment screw passes through the left end and the right end of the Y-direction adjustment frame and is rotatably connected to the Y-direction adjustment frame. The Y-direction adjustment seat is connected to the Y-direction adjustment screw, and the X-direction adjustment structure is mounted on the Y-direction adjustment seat.

[0014] Further, the X-direction adjustment structure includes an X-direction fixed seat, an X-direction rotating seat, and at least two X-direction adjustment screws. The X-direction rotating seat is rotatably connected to the Y-direction adjustment seat through a rotating positioning shaft. The X-direction fixed seat is connected to the upper end of the Y-direction adjustment seat. At least two threaded holes are provided on the X-direction fixed seat. The X-direction adjustment screws pass through the threaded holes and are threadedly connected to the X-direction fixed seat. The bottom end of the X-direction adjustment screw abuts against the top end of the X-direction rotating seat.

[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0016] When the present utility model is in use, the laser excitation component is rotatably connected to the mounting bracket through the light source fixing arm, so that the laser light source on the laser excitation component can swing around the X-axis to adjust the light source irradiation angle. There is only one adjustment variable for the light source adjustment, which simplifies the imaging adjustment work. At the same time, based on the principle of photoluminescence, a laser with a specific wavelength emitted by the laser excitation component is used as the excitation light source to provide photons with a certain amount of energy. The ground state electrons in the silicon wafer to be measured enter the excited state after absorbing these photons and release near-infrared light with a specific wave peak. Then, an infrared camera mechanism is used for photosensing and imaging to determine whether there are hidden crack defects in the sample, making the imaging simpler and the defect parameter detection reliable and accurate. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 It is a schematic diagram of the overall structure of the present utility model;

[0019] Figure 2 It is Figure 1 the enlarged view of part A in

[0020] Figure 3 It is a schematic diagram of the overall optical path of the present utility model.

[0021] The names of the components marked in the figure are as follows:

[0022] 1. Conveyor streamline; 2. Laser excitation mechanism; 3. Infrared camera mechanism; 4. Mounting bracket; 5. Laser excitation component; 6. Light source fixing arm; 7. Arc groove; 8. Positioning post; 9. First conveyor component; 10. Second conveyor component; 11. Baffle; 12. Background board; 13. Infrared camera; 14. Camera adjustment component; 15. Z-direction adjustment structure; 16. Y-direction adjustment structure; 17. X-direction adjustment structure; 151. Z-direction adjustment seat; 152. Z-direction screw; 153. Z-direction adjustment frame; 161. Y-direction adjustment seat; 162. Y-direction adjustment screw; 163. Y-direction adjustment frame; 171. X-direction fixing seat; 172. X-direction rotating seat; 173. X-direction adjustment screw; 18. Silicon wafer. Detailed implementation manners

[0023] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will, in combination with the accompanying drawings and preferred embodiments, describe in detail the specific implementation manners, structures, features and their effects of the present invention as follows.

[0024] Embodiment: Please refer to Figures 1 - 3 , a device for detecting hidden cracks in silicon wafers based on photoluminescence, including a conveyor streamline 1, a laser excitation mechanism 2 and an infrared camera mechanism 3. The conveyor streamline 1 includes a first conveyor component 9 and a second conveyor component 10 arranged in sequence along the conveying direction of the silicon wafer 18. There is a gap between the output end of the first conveyor component 9 and the input end of the second conveyor component 10. Both the first conveyor component 9 and the second conveyor component 10 are prior arts and will not be elaborated herein. The laser excitation mechanism 2 includes a mounting bracket 4 and a laser excitation component 5 mounted on the mounting bracket 4. The laser excitation component 5 is mounted on one side of the gap. The laser excitation component 5 includes a laser light source. Both sides of the mounting bracket 4 are respectively mounted on both sides of the conveyor streamline 1, and the mounting bracket 4 is located directly above the gap. Both ends of the laser excitation component 5 are rotationally connected to the mounting bracket 4 through a rotating rod at one end of the light source fixing arm 6. The rotating rod is provided with an external thread, and the rotation of the rod and the mounting bracket 4 can be locked through a nut. The laser light source on the laser excitation component 5 can swing around the X-axis to adjust the light source irradiation angle. Having only one adjustment variable for the light source adjustment simplifies the imaging adjustment work; Arc grooves 7 are provided on both sides of the mounting bracket 4. A positioning post 8 is provided at one end of the light source fixing arm 6. The positioning post 8 can be a locking bolt. The positioning post 8 passes through the arc groove 7 and slides in the arc groove 7. The arc groove 7 can limit the sliding position of the positioning post 8, thereby restricting the swinging angle of the laser excitation component 5 and avoiding excessive adjustment of the light source irradiation angle of the laser excitation component 5.

[0025] The infrared camera mechanism 3 is installed on the mounting bracket 4 and is located above the laser excitation component 5. The infrared camera mechanism 3 includes an infrared camera 13 and a camera adjustment component 14. The infrared camera 13 is installed on the camera adjustment component 14. The infrared camera 13 is a high-sensitivity infrared camera 13. The infrared camera 13 and the laser excitation component 5 form a basic excitation. Based on the principle of photoluminescence, a laser with a specific wavelength is used as the excitation light source to provide photons with a certain amount of energy. The ground-state electrons in the silicon wafer 18 to be measured enter the excited state after absorbing these photons and release near-infrared light with a peak wavelength of about 1150 nm. Then, the high-sensitivity and high-resolution infrared camera 13 is used for photosensing and imaging. After imaging, the light intensity is proportional to the concentration of non-equilibrium minority carriers at the corresponding position. Since defects will cause a decrease in the concentration of minority carriers in this area, thereby weakening its fluorescence effect, it will appear as dark spots, lines, or a certain area after imaging. Therefore, the presence of hidden crack defects in the sample wafer can be judged by photoluminescence, making the imaging simpler and the defect parameter detection reliable and accurate. A baffle 11 is installed on the mounting bracket 4 and is located directly above the interval, and a background plate 12 is installed on the mounting bracket 4 and is located directly below the interval. The functions of the baffle 11 and the background plate 12 are to make the photoluminescence imaging of the silicon wafer 18 more uniform and eliminate the interference of surrounding objects, and to prevent small fragments from upstream from falling on the detection position during the batch production detection of the silicon wafer 18, generating an interference signal for detection and causing misdetection or machine downtime.

[0026] The camera adjustment component 14 includes a Z-direction adjustment structure 15, a Y-direction adjustment structure 16, and an X-direction adjustment structure 17. The Y-direction adjustment structure 16 is installed on the Z-direction adjustment structure 15, and the X-direction adjustment structure 17 is installed on the Y-direction adjustment structure 16. The Z-direction adjustment structure 15 includes a Z-direction fixed plate, a Z-direction screw 152, a Z-direction adjustment frame 153, and a Z-direction adjustment seat 151. The Z-direction screw 152 passes through the upper and lower ends of the Z-direction adjustment frame 153 and is rotatably connected to the Z-direction adjustment frame 153. One end of the Z-direction screw 152 located at the upper end of the Z-direction adjustment frame 153 is connected with an adjustment knob. The Z-direction adjustment seat 151 is connected to the Z-direction screw 152, and the Z-direction fixed plate is installed on the Z-direction adjustment seat 151. The Z-direction adjustment structure 15 further includes a guide post, and the guide post is installed on the Z-direction adjustment frame 153 and is slidably connected to the Z-direction adjustment seat 151. When making adjustments in the Z direction, turn the adjustment knob to drive the Z-direction screw 152 to rotate. Under the guiding action of the guide post, drive the Z-direction adjustment seat 151 to move up and down stably, which can adjust the working distance between the infrared camera 13 and the silicon wafer 18, ensure a suitable field of view and clear imaging, and has the characteristics of convenience and low cost.

[0027] The Y - direction adjustment structure 16 includes a Y - direction adjustment base 161, a Y - direction adjustment screw 162, and a Y - direction adjustment frame 163. The Y - direction adjustment frame 163 is installed on the Z - direction fixed plate. The Y - direction adjustment screw 162 passes through the left and right ends of the Y - direction adjustment frame 163 and is rotatably connected to the Y - direction adjustment frame 163. The Y - direction adjustment base 161 is connected to the Y - direction adjustment screw 162, and the X - direction adjustment structure 17 is installed on the Y - direction adjustment base 161. When making adjustments in the Y - direction, the Y - direction adjustment screw 162 rotates, driving the Y - direction adjustment base 161 to move steadily left and right, making the imaging adjustment of the infrared camera 13 more sensitive and convenient.

[0028] The X - direction adjustment structure 17 includes an X - direction fixed base 171, an X - direction rotating base 172, and two X - direction adjustment screws 173. The X - direction rotating base 172 is rotatably connected to the Y - direction adjustment base 161 through a rotating positioning shaft. The X - direction fixed base 171 is connected to the upper end of the Y - direction adjustment base 161. At least two threaded holes are provided on the X - direction fixed base 171. The X - direction adjustment screws 173 pass through the threaded holes and are threadedly connected to the X - direction fixed base 171, and the bottom ends of the X - direction adjustment screws 173 abut against the top end of the X - direction rotating base 172. By adjusting the two X - rotation adjustment screws, under the action of the rotating positioning shaft, the X - direction rotating base 172 and the infrared camera 13 on the X - direction rotating base 172 can swing around the X - axis by a certain angle, making the imaging adjustment of the infrared camera 13 more sensitive and convenient.

[0029] The working principle of this embodiment: Before the silicon wafer 18 is transported by the first transport assembly 9 and the second transport assembly 10 for detection, when adjusting the laser excitation assembly 5, the laser light source on the laser excitation assembly 5 swings around the X - axis to adjust the light source irradiation angle under the action of the light source fixing arm 6, and at the same time, the light source fixing arm 6 drives the laser excitation assembly 5 to swing along the trajectory of the arc groove 7. When adjusting the infrared camera 13, the Z - direction screw 152 rotates, driving the Z - direction adjustment base 151 to move steadily up and down to adjust the working distance between the infrared camera 13 and the silicon wafer 18; the Y - direction adjustment screw 162 rotates, driving the Y - direction adjustment base 161 to move steadily left and right; by adjusting the two X - rotation adjustment screws, under the action of the rotating positioning shaft, the X - direction rotating base 172 and the infrared camera 13 on the X - direction rotating base 172 can swing around the X - axis by a certain angle. By adjusting the laser light source and the infrared camera 13 in this way, the device has the characteristics of fewer adjustment variables, simpler imaging, more convenient debugging operation, and lower cost.

[0030] It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "upper", "lower", "left", "right", "front", "rear" and similar expressions used herein are for illustrative purposes only.

[0031] The above are only the preferred embodiments of the present invention, and do not impose any formal limitations on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the technical content disclosed above within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An apparatus for detecting hidden cracks in silicon wafers based on photoluminescence, characterized in that: It includes a conveying streamline (1), a laser excitation mechanism (2) and an infrared camera mechanism (3). The laser excitation mechanism (2) includes a mounting bracket (4) and a laser excitation component (5) mounted on the mounting bracket (4). Both sides of the mounting bracket (4) are respectively mounted on both sides of the conveying streamline (1). The infrared camera mechanism (3) is mounted on the mounting bracket (4) and is located above the laser excitation component (5). Both ends of the laser excitation component (5) are rotatably connected to the mounting bracket (4) through a light source fixing arm (6).

2. The device for detecting the hidden crack of the silicon wafer based on photoluminescence according to claim 1, wherein: Arc grooves (7) are provided on both sides of the mounting bracket (4). One end of the light source fixing arm (6) is provided with a positioning post (8). The positioning post (8) passes through the arc groove (7) and slides in the arc groove (7).

3. The device for detecting the hidden crack of the silicon wafer based on photoluminescence according to claim 1, wherein: The conveying streamline (1) includes a first conveying component (9) and a second conveying component (10) arranged in sequence along the conveying direction of the silicon wafer (18). There is a gap between the output end of the first conveying component (9) and the input end of the second conveying component (10). The mounting bracket (4) is located directly above the gap, and the laser excitation component (5) is mounted on one side of the gap.

4. The device for detecting the hidden crack of the silicon wafer based on photoluminescence according to claim 3, wherein: A baffle (11) is mounted on the mounting bracket (4) and is located directly above the gap.

5. The device for detecting the hidden crack of the silicon wafer based on photoluminescence according to claim 3, wherein: A background plate (12) is mounted on the mounting bracket (4) and is located directly below the gap.

6. The device for detecting the hidden crack of the silicon wafer based on photoluminescence according to claim 1, wherein: The infrared camera mechanism (3) includes an infrared camera (13) and a camera adjustment component (14). The infrared camera (13) is mounted on the camera adjustment component (14).

7. The device for detecting the hidden crack of the silicon wafer based on photoluminescence according to claim 6, wherein: The camera adjustment component (14) includes a Z-direction adjustment structure (15), a Y-direction adjustment structure (16) and an X-direction adjustment structure (17). The Y-direction adjustment structure (16) is mounted on the Z-direction adjustment structure (15), and the X-direction adjustment structure (17) is mounted on the Y-direction adjustment structure (16).

8. The device for detecting hidden cracks in silicon wafers based on photoluminescence according to claim 7, wherein: The Z-direction adjustment structure (15) includes a Z-direction fixing plate, a Z-direction screw (152), a Z-direction adjustment frame (153) and a Z-direction adjustment seat (151). The Z-direction screw (152) passes through the upper and lower ends of the Z-direction adjustment frame (153) and is rotatably connected to the Z-direction adjustment frame (153). The Z-direction adjustment seat (151) is connected to the Z-direction screw (152), and the Z-direction fixing plate is mounted on the Z-direction adjustment seat (151).

9. The device for detecting the hidden cracks of the silicon wafer based on photoluminescence according to claim 7, characterized in that: The Y-direction adjustment structure (16) includes a Y-direction adjustment seat (161), a Y-direction adjustment screw (162) and a Y-direction adjustment frame (163). The Y-direction adjustment frame (163) is mounted on the Z-direction fixing plate. The Y-direction adjustment screw (162) passes through the left and right ends of the Y-direction adjustment frame (163) and is rotatably connected to the Y-direction adjustment frame (163). The Y-direction adjustment seat (161) is connected to the Y-direction adjustment screw (162), and the X-direction adjustment structure (17) is mounted on the Y-direction adjustment seat (161).

10. The device for detecting the hidden crack of the silicon wafer based on photoluminescence according to claim 9, wherein: The X-direction adjustment structure (17) includes an X-direction fixed seat (171), an X-direction rotating seat (172), and at least two X-direction adjustment screws (173). The X-direction rotating seat (172) is rotationally connected to the Y-direction adjustment seat (161) through a rotation positioning shaft. The X-direction fixed seat (171) is connected to the upper end of the Y-direction adjustment seat (161). At least two threaded holes are formed in the X-direction fixed seat (171). The X-direction adjustment screw (173) passes through the threaded hole and is threadedly connected to the X-direction fixed seat (171). The bottom end of the X-direction adjustment screw (173) abuts against the top end of the X-direction rotating seat (172).

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