Wafer defect detection system
By combining ultraviolet and infrared laser scattering detection technologies, simultaneous detection of defects on the wafer surface and inside the wafer is achieved, solving the problem of low efficiency in traditional detection methods and improving detection efficiency.
Patent Information
- Application Number
- CN202422001001.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-16
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-08-16
AI Technical Summary
Traditional wafer defect detection methods cannot fully assess wafer integrity, have low detection efficiency, and cannot simultaneously detect surface and internal defects.
By combining ultraviolet laser scattering detection technology and infrared laser scattering detection technology, wafer defects can be detected simultaneously using ultraviolet and infrared lasers. Surface and internal defects can be determined using ultraviolet and infrared light, achieving synchronous detection.
Simultaneous detection of wafer surface and internal defects was achieved in the same inspection process, significantly improving inspection efficiency.
Smart Images
Figure CN223551598U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of optical inspection technology, and in particular to a wafer defect detection system. Background Technology
[0002] In the semiconductor manufacturing process, defects on the wafer surface and inside have a significant impact on yield and product performance.
[0003] Traditional wafer defect detection methods often focus on a single detection method, such as using only ultraviolet lasers to detect surface defects or infrared thermal imaging to detect internal defects. These methods cannot comprehensively assess the integrity of the wafer and have low detection efficiency. Utility Model Content
[0004] This invention provides a wafer defect detection system that combines ultraviolet laser scattering detection technology and infrared laser scattering detection technology. This system can simultaneously detect wafer surface and internal defects in the same detection process, significantly improving detection efficiency.
[0005] This utility model provides a wafer defect detection system, including a first laser, a second laser, a first detector, a second detector, and a processor, wherein the first detector and the second detector are both connected to the processor;
[0006] The ultraviolet laser beam output from the first laser is incident on the surface of the wafer under test, and the ultraviolet light scattered by the surface defects of the wafer under test is incident on the first detector.
[0007] The infrared laser beam output by the second laser is incident on the wafer under test, and part of the infrared laser beam is transmitted into the interior of the wafer under test. The infrared light scattered by the internal defects of the wafer under test is incident on the second detector.
[0008] The processor determines the surface and internal defects of the wafer under test based on the signals from the first and second detectors.
[0009] Optionally, the wafer defect detection system further includes a motion module, wherein the wafer under test is connected to the motion module, and the motion module drives the wafer under test to move to achieve scanning of the wafer under test, and / or
[0010] The first laser and the second laser are connected to the motion module, and the motion module drives the first laser and the second laser to move in order to scan the wafer under test.
[0011] Optionally, the motion module uses linear scanning, or the motion module uses spiral scanning.
[0012] Optionally, the wafer defect detection system further includes a first incident module and a second incident module, wherein the first incident module and the second incident module include at least one converging lens;
[0013] The first incident module is located between the first laser and the wafer under test. The ultraviolet laser beam output by the first laser is focused by the first incident module and then incident on the surface of the wafer under test.
[0014] The second incident module is located between the second laser and the wafer under test. The infrared laser beam output by the second laser is focused by the second incident module and then incident on the wafer under test and transmitted into the interior of the wafer under test.
[0015] Optionally, the first incident module focuses the spot diameter of the ultraviolet laser beam to 10μm to 200μm, and the second incident module focuses the spot diameter of the infrared laser beam to 10μm to 200μm.
[0016] Optionally, the wafer defect detection system further includes a first reflection module and a second reflection module;
[0017] The first reflection module is located between the wafer under test and the first detector. Ultraviolet light scattered by the surface defects of the wafer under test is reflected by the first reflection module to the first detector.
[0018] The second reflection module is located between the wafer under test and the second detector. Infrared light scattered by internal defects of the wafer under test is reflected by the second reflection module to the second detector.
[0019] Optionally, the wafer defect detection system further includes a scattering module, which includes a scattered light collection device and a dichroic mirror. The dichroic mirror is located on the side of the scattered light collection device away from the wafer under test. The first detector is located at the first output end of the dichroic mirror, and the second detector is located at the second output end of the dichroic mirror.
[0020] The ultraviolet light scattered by the surface defects of the wafer under test shares a portion of the optical path with the infrared light scattered by the internal defects of the wafer under test. The ultraviolet light and the infrared light are incident on the scattered light collection device and converge to the dichroic mirror. The dichroic mirror transmits the ultraviolet light and the infrared light to the first detector and the second detector, respectively.
[0021] Optionally, the scattering module further includes a first filter and a second filter, wherein the first filter is located between the dichroic mirror and the first detector, and the second filter is located between the dichroic mirror and the second detector.
[0022] Optionally, the incident angle of the ultraviolet laser beam output by the first laser onto the wafer under test is 60° to 70°.
[0023] The infrared laser beam output by the second laser is incident at an angle of 60° to 70° onto the wafer under test.
[0024] Optionally, the wavelength of the ultraviolet laser beam is less than or equal to 355 nm, and the wavelength of the infrared laser beam is greater than or equal to 1100 nm.
[0025] The wafer defect detection system provided in this embodiment combines ultraviolet laser scattering detection technology and infrared laser scattering detection technology. It utilizes both ultraviolet and infrared lasers to simultaneously detect wafer defects and determines surface and internal defects of the wafer under test based on the scattered ultraviolet and infrared light. This achieves simultaneous detection of wafer surface and internal defects within the same detection process, improving detection efficiency.
[0026] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description
[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a schematic diagram of the structure of a wafer defect detection system provided in an embodiment of the present invention;
[0029] Figure 2 This is a schematic diagram of another wafer defect detection system provided in this embodiment of the present invention;
[0030] Figure 3 This is a schematic diagram of the structure of another wafer defect detection system provided in this embodiment of the present invention;
[0031] Figure 4 This is a schematic diagram of the motion trajectory using linear scanning;
[0032] Figure 5 This is a schematic diagram of the motion trajectory using spiral scanning;
[0033] Figure 6This is a schematic diagram of the structure of another wafer defect detection system provided in this embodiment of the present invention;
[0034] Figure 7 This is a schematic diagram of the scattering module. Detailed Implementation
[0035] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.
[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0037] Figure 1 This is a schematic diagram of a wafer defect detection system provided in an embodiment of the present invention. This embodiment is applicable to the detection of wafer defects.
[0038] like Figure 1The wafer defect detection system shown includes a first laser 1, a second laser 2, a first detector 10, a second detector 11, and a processor 15. Both the first detector 10 and the second detector 11 are connected to the processor 15. An ultraviolet laser beam output from the first laser 1 is incident on the surface of the wafer 14 under test. Ultraviolet light scattered by surface defects of the wafer 14 is incident on the first detector 11. An infrared laser beam output from the second laser 2 is incident on the wafer 14 under test. Part of the infrared laser beam penetrates into the interior of the wafer 14, and infrared light scattered by internal defects of the wafer 14 is incident on the second detector 11. Optionally, the incident angle of the ultraviolet laser beam output from the first laser 1 onto the wafer under test is preferably 60°–70°, and the incident angle of the infrared laser beam output from the second laser 2 onto the wafer under test is preferably 60°–70°, as this incident angle provides higher detection sensitivity. The processor 15 determines the surface and internal defects of the wafer 14 under test based on the signals from the first detector 10 and the second detector 11.
[0039] Optionally, the wavelength of the ultraviolet laser beam is less than or equal to 355 nm, and the wavelength of the infrared laser beam is greater than or equal to 1100 nm. According to the Rayleigh scattering principle, the shorter the wavelength, the higher the detection sensitivity. Therefore, it is preferred that the wavelength of the ultraviolet laser beam is less than or equal to 355 nm. The infrared laser beam needs to ensure that it has a sufficiently high transmittance to the wafer. Therefore, it is preferred that the wavelength of the infrared laser beam is greater than or equal to 1100 nm.
[0040] For example, refer to Figure 1The first laser 1 outputs an ultraviolet laser beam, which is incident on the surface of the wafer 14 under test. When the ultraviolet laser beam hits defects on the surface of the wafer 14, such as pits, bumps, scratches, etc., it is scattered. A portion of the scattered light is incident on the first detector 10 and received by the first detector 10. The first detector 10 then detects the defects present on the surface of the wafer 14 at the corresponding locations based on the received ultraviolet laser beam. The second laser 2 outputs an infrared laser beam, which is incident on the wafer 14 under test. Because infrared lasers have high transmittance to wafers, a portion of the infrared laser beam can penetrate the wafer and irradiate internal defects on the wafer 14, such as voids, cracks, uneven doping, etc. The infrared laser beam is scattered, and a portion of the scattered light is incident on the second detector 11 and received by the second detector 11. The second detector 11 then detects the internal defects present on the wafer 14 at the corresponding locations based on the received infrared laser beam. The processor 15 draws a defect distribution map on the wafer surface and a defect distribution map inside the wafer based on the signals from the first detector 10 and the second detector 11. It is understandable that a portion of the infrared laser light will be scattered by the surface of the wafer 14 under test. Some of this scattered light will also be received by the second detector 11. That is, the second detector 11 receives a combination of surface and internal signals, which cannot be directly distinguished by the detector. In specific implementation, the surface signal information measured by the ultraviolet laser can be subtracted during signal processing to obtain the defect signal inside the wafer 14 under test.
[0041] This invention provides a wafer defect detection system, comprising a first laser 1, a second laser 2, a first detector 10, a second detector 11, and a processor 15. The first laser 1, the first detector 10, and the processor 15 enable the detection and location of surface defects on the wafer; the second laser 2, the second detector 11, and the processor 15 enable the detection and location of internal defects on the wafer. This wafer defect detection system achieves simultaneous detection of surface and internal defects within the same detection process, improving detection efficiency.
[0042] Optionally, the wafer defect detection system may also include a motion module, wherein the wafer under test is connected to the motion module, and the motion module drives the wafer under test to move in order to scan the wafer under test, and / or a first laser and a second laser are connected to the motion module, and the motion module drives the first laser and the second laser to move in order to scan the wafer under test.
[0043] For example, Figure 2 This is a schematic diagram of another wafer defect detection system provided in this embodiment of the present invention. Figure 3 This is a schematic diagram of another wafer defect detection system provided in this embodiment of the present invention. (Reference) Figure 2The wafer under test 14 is connected to the motion module 16, which drives the wafer under test 14 to move in order to achieve scanning of the wafer under test 14; Reference Figure 3 The first laser 1 and the second laser 2 are connected to the motion module 16, which drives the first laser 1 and the second laser 2 to scan the wafer 14 under test. In other embodiments, the motion module 16 can also be configured to drive the first laser 1, the second laser 2 and the wafer 14 under test to move simultaneously, and the specific implementation can be designed according to the actual situation.
[0044] After the lasers output from the first laser 1 and the second laser 2 illuminate the wafer 14 under test, the motion module 16 moves the wafer 14 to ensure that the lasers output from the first laser 1 and the second laser 2 completely scan the wafer 14. Alternatively, the motion module 16 can be connected to the first laser 1 and the second laser 2, allowing the first laser 1 and the second laser 2 to move actively and completely scan the wafer 14. Furthermore, the two methods can be combined by connecting multiple motion modules to the wafer, the first laser 1, and the second laser 2 respectively, to achieve coordinated movement between the first laser 1 and the second laser 2, ensuring that the lasers output from the first laser 1 and the second laser 2 completely scan the wafer 14.
[0045] Optionally, the motion module can use linear scanning or spiral scanning. Figure 4 This is a schematic diagram of the motion trajectory using linear scanning. Figure 5 This is a schematic diagram of the motion trajectory using spiral scanning. (For reference) Figure 4 and Figure 5 , Figure 4 The motion trajectory of the linear scan is shown. Figure 5 The motion trajectory of the spiral scan is shown.
[0046] Figure 6 This is a schematic diagram of another wafer defect detection system provided in this embodiment of the present invention. Optional, refer to... Figure 6 The wafer defect detection system also includes a first incident module 3 and a second incident module 4, each including at least one converging lens. The first incident module 3 is located between the first laser 1 and the wafer under test. The ultraviolet laser beam output from the first laser 1 is converged by the first incident module 3 and then incident on the surface of the wafer under test. The second incident module 4 is located between the second laser 2 and the wafer under test. The infrared laser beam output from the second laser 2 is converged by the second incident module 4 and then incident on the wafer under test and transmitted into the interior of the wafer.
[0047] For example, continue to refer to Figure 6The ultraviolet laser output from the first laser 1 is incident on the first incident module 3, and the infrared laser output from the second laser 2 is incident on the second incident module 4. The laser beams are focused, their energy is more concentrated, and the spot of light illuminating the wafer is smaller. When the wafer defects are irradiated, the processor can obtain more accurate coordinate positions.
[0048] Optionally, the first incident module 3 focuses the spot diameter of the ultraviolet laser beam to 10μm to 200μm, and the second incident module 4 focuses the spot diameter of the infrared laser beam to 10μm to 200μm.
[0049] Optional, continue to refer to Figure 6 The wafer defect detection system also includes a first reflection module 5 and a second reflection module 6. The first reflection module 5 is located between the wafer under test and the first detector. Ultraviolet light scattered by surface defects of the wafer under test is reflected by the first reflection module 5 to the first detector. The second reflection module 6 is located between the wafer under test and the second detector. Infrared light scattered by internal defects of the wafer under test is reflected by the second reflection module 6 to the second detector.
[0050] The function of the first reflection module 5 and the second reflection module 6 is to focus the scattered light onto the detector in order to obtain the location information of the wafer defects and the information of the wafer surface undulations. Their structures are not limited here. Ultraviolet light scattered by defects on the surface of the wafer being tested passes through the first reflection module 5 and is reflected onto the first detector 10. Infrared light scattered by defects inside the wafer being tested passes through the second reflection module 6 and is reflected onto the second detector 11.
[0051] Optional, see reference Figure 6 The wafer defect detection system also includes a scattering module 7. Figure 7 This is a schematic diagram of the scattering module. The scattering module includes a scattered light collection device 8 and a dichroic mirror 9. The dichroic mirror 9 is located on the side of the scattered light collection device 8 away from the wafer under test. The first detector 10 is located at the first output terminal of the dichroic mirror 9, and the second detector 11 is located at the second output terminal of the dichroic mirror 9.
[0052] The light paths of ultraviolet light scattered by surface defects of the wafer under test and infrared light scattered by internal defects of the wafer under test are shared. The ultraviolet light and infrared light are incident on the scattered light collection device and converge to the dichroic mirror 9. The dichroic mirror 9 transmits the ultraviolet light and infrared light to the first detector 10 and the second detector 11 respectively.
[0053] For example, refer to Figure 7 First laser and second laser ( Figure 7The laser light (not shown) irradiates defects on the wafer and is scattered. The scattered light passes through the scattered light collection device 8 and converges to the dichroic mirror 9. The dichroic mirror 9 has high transmittance for ultraviolet light and high reflectivity for infrared light. The ultraviolet light in the scattered light is transmitted through the dichroic mirror 9 and enters the first detector 10; the infrared light in the scattered light is reflected by the dichroic mirror 9 and enters the second detector 11.
[0054] Optional, see reference Figure 7 The scattering module also includes a first filter 12 and a second filter 13. The first filter 12 is located between the dichroic mirror 9 and the first detector 10, and the second filter 13 is located between the dichroic mirror 9 and the second detector 11.
[0055] For example, the first filter 12 can transmit ultraviolet light while filtering out infrared light; the second filter 13 can transmit infrared light while filtering out ultraviolet light. Adding filters can further filter out stray light, making the detection results more accurate.
[0056] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.
Claims
1. A wafer defect detection system, characterized in that, It includes a first laser, a second laser, a first detector, a second detector, and a processor, wherein the first detector and the second detector are both connected to the processor; The ultraviolet laser beam output by the first laser is incident on the surface of the wafer under test, and the ultraviolet light scattered by the surface defects of the wafer under test is incident on the first detector; The infrared laser beam output by the second laser is incident on the wafer under test, and part of the infrared laser beam is transmitted into the interior of the wafer under test. The infrared light scattered by the internal defects of the wafer under test is incident on the second detector. The processor determines the surface and internal defects of the wafer under test based on the signals from the first detector and the second detector.
2. The wafer defect detection system according to claim 1, characterized in that, It also includes a motion module, to which the wafer under test is connected, the motion module driving the wafer under test to move in order to achieve scanning of the wafer under test, and / or The first laser and the second laser are connected to the motion module, and the motion module drives the first laser and the second laser to move in order to scan the wafer under test.
3. The wafer defect detection system according to claim 2, characterized in that, The motion module uses linear scanning, or the motion module uses spiral scanning.
4. The wafer defect detection system according to claim 1, characterized in that, It also includes a first incident module and a second incident module, wherein the first incident module and the second incident module include at least one converging lens; The first incident module is located between the first laser and the wafer under test. The ultraviolet laser beam output by the first laser is focused by the first incident module and then incident on the surface of the wafer under test. The second incident module is located between the second laser and the wafer under test. The infrared laser beam output by the second laser is focused by the second incident module and then incident on the wafer under test and transmitted into the interior of the wafer under test.
5. The wafer defect detection system according to claim 4, characterized in that, The first incident module focuses the spot diameter of the ultraviolet laser beam to 10μm to 200μm, and the second incident module focuses the spot diameter of the infrared laser beam to 10μm to 200μm.
6. The wafer defect detection system according to claim 1, characterized in that, It also includes a first reflection module and a second reflection module; The first reflection module is located between the wafer under test and the first detector. Ultraviolet light scattered by the surface defects of the wafer under test is reflected by the first reflection module to the first detector. The second reflection module is located between the wafer under test and the second detector. Infrared light scattered by internal defects of the wafer under test is reflected by the second reflection module to the second detector.
7. The wafer defect detection system according to claim 1, characterized in that, It also includes a scattering module, which includes a scattered light collection device and a dichroic mirror. The dichroic mirror is located on the side of the scattered light collection device away from the wafer under test. The first detector is located at the first output end of the dichroic mirror, and the second detector is located at the second output end of the dichroic mirror. The ultraviolet light scattered by the surface defects of the wafer under test shares a portion of the optical path with the infrared light scattered by the internal defects of the wafer under test. The ultraviolet light and the infrared light are incident on the scattered light collection device and converge to the dichroic mirror. The dichroic mirror transmits the ultraviolet light and the infrared light to the first detector and the second detector, respectively.
8. The wafer defect detection system according to claim 7, characterized in that, The scattering module further includes a first filter and a second filter, wherein the first filter is located between the dichroic mirror and the first detector, and the second filter is located between the dichroic mirror and the second detector.
9. The wafer defect detection system according to claim 1, characterized in that, The ultraviolet laser beam output by the first laser is incident at an angle of 60° to 70° onto the wafer under test; The infrared laser beam output by the second laser is incident at an angle of 60° to 70° onto the wafer under test.
10. The wafer defect detection system according to claim 1, characterized in that, The wavelength of the ultraviolet laser beam is less than or equal to 355 nm, and the wavelength of the infrared laser beam is greater than or equal to 1100 nm.