Device and method for confirming crack position of bonded wafer

Abstract

The invention provides a device and method for confirming the crack position of a bonded wafer, and the device comprises a bonded wafer placement part, a light source, an image sensing part, an insertion piece part, and a shading part, the insertion piece part is disposed at the outer side of the bonded wafer placement part, and an insertion piece is inserted into the bonded wafer for confirming the crack position; and the bonding wafer placing part, the light source, the image sensing part and the sheet inserting part are covered in the shading part. The wafer position can be observed in real time through the image sensing technology, the wafer defect can be observed conveniently, and the wafer crack generation position can be accurately positioned. And then the wafer insertion part is inserted into the crack generation position of the wafer, so that the generation source of the wafer crack can be found more accurately, and the personnel can be assisted to improve the process. The crack generation position of the bonding wafer can be accurately positioned by using a simple structure, the wafer detection efficiency is improved, and the phenomena of wrong detection and missing detection caused by manual detection are reduced.

Description

Technical Field

[0001] This application belongs to the field of semiconductor manufacturing, and specifically relates to an apparatus and method for confirming the location of cracks in bonded wafers. Background Technology

[0002] Lithium niobate (LNiO) is a functional crystalline material with excellent piezoelectric, electro-optic, and nonlinear optical properties, playing a crucial role in optoelectronics, radio frequency (RF) communication, and sensing. In recent years, with the development of heterogeneous integration technology, LNiO bonded wafers have become one of the core directions of next-generation photonic integration platforms. LNiO bonded wafers utilize advanced wafer bonding technologies (such as direct bonding and dielectric-assisted bonding) to combine single-crystal LNiO thin films with substrates such as silicon, silicon nitride (SiN), or silicon-on-insulator (SOI) to form heterostructures. Through nanoscale thin film fabrication and micro / nano fabrication processes, low-loss optical waveguides, high-speed electro-optic modulators, and high-efficiency nonlinear optical devices can be realized, significantly improving the bandwidth and energy efficiency of optical communication systems. In recent years, with the gradual improvement of LNiO bonding technology, LNiO bonded wafers have also shown great potential in 5G / 6G RF front-ends, quantum optics, and microwave photonics, and have experienced rapid development in optoelectronic devices, all-optical signal processing, optical data storage, and optical sensing.

[0003] After lithium niobate is bonded to silicon carbide wafers, the wafers are prone to cracking due to stress and other reasons during the bonding annealing process. However, since both materials are transparent, it is difficult to determine the location of the bonding cracks and which type of wafer they occur on. Therefore, there is an urgent need for a device to detect and determine the cracks generated on the wafers.

[0004] The existing technologies for detecting wafer crack defects mainly include the following: 1. Automated Optical Inspection (AOI) technology for wafer defects, such as patent number CN115753822A, entitled "Wafer Defect Detection Device," which uses light sources and image sensors for detection. However, this technology can only detect the presence of cracks in the wafer but cannot pinpoint the exact location of the crack. 2. CN 119164969 A, "Wafer Quality Inspection Method in an Ultra-Clean Environment," discloses the use of laser scanning, infrared thermal imagers, and ultrasonic detection technologies. This technology is too precise for practical applications and has low efficiency for inspecting bonded wafers. 3. CN118533860A discloses a wafer crack detection device and method that uses photosensitive sensing technology to output information to accurately detect the presence of cracks in the wafer. This technology is only suitable for single-wafer applications and cannot pinpoint the location of cracks in bonded substrates. Summary of the Invention

[0005] To address the aforementioned problems, this application proposes a device for confirming the location of cracks in bonded wafers, comprising: a bonded wafer placement section, a light source, an image sensing section, an insert section, and a light-shielding section. The light source is disposed above the bonded wafer placement section, and the image sensing section is disposed above the bonded wafer placement section to transmit an image to a display device. The insert section is disposed outside the bonded wafer placement section, and inserts a die into the bonded wafer to confirm the crack location. The light-shielding section covers the bonded wafer placement section, the light source, the image sensing section, and the insert section within a light-shielding section.

[0006] Furthermore, the insert portion includes an insert clamping portion, which is a claw structure. The contact surface between the claw structure and the insert is provided with an anti-slip structure, which is an array of hemispherical protrusions. The diameter of the hemispherical protrusions is 0.5-1mm, and the spacing between adjacent hemispherical protrusions is 1-2mm.

[0007] Furthermore, the hemispherical protrusion is made of polyurethane material with a Shore hardness of 30-50A.

[0008] Furthermore, the insert is made of one or more composite materials selected from tungsten carbide, polycrystalline diamond, cubic boron nitride, zirconium oxide, and aluminum oxide.

[0009] Preferably, the selection of the insert material should comprehensively consider multiple factors, including hardness, rigidity, chemical inertness, machinability, and cost. The insert's hardness must be significantly higher than the wafer's hardness to ensure it does not wear down during insertion, avoid contaminating the wafer, and ensure precise wedging into the wafer bonding interface. The insert needs high rigidity to ensure it does not bend, deform, or vibrate during insertion, avoiding inaccurate positioning, scratching the wafer during insertion, or causing crack propagation that affects target crack observation. The insert has excellent chemical stability; it will not react with the wafer, nor will it oxidize and shed particles when exposed to air. The insert material needs to be machinable into an ultra-thin, ultra-flat, and sharp-edged blade shape. Furthermore, since the insert acts as a background layer at the wafer bonding interface, facilitating crack observation, it should be made of an opaque, colored material.

[0010] Preferably, the insert near the insertion end is a smooth mirror surface, and the contact surface with the claw structure has a certain roughness (maintaining the rough surface state after grinding, without the need for polishing treatment), which generates a very strong mechanical interlocking effect with the polyurethane hemispherical protrusion, resulting in excellent anti-slip effect.

[0011] Furthermore, the insert part also includes a vertical drive assembly for lifting and lowering the insert clamping part, and a horizontal drive assembly for horizontal linear reciprocating motion of the insert clamping part; the stroke of the vertical drive assembly is 50-150mm; the horizontal drive assembly is driven by a linear motor with a stroke of 10-30μm.

[0012] Furthermore, the horizontal drive component uses a motor encoder to provide real-time position feedback, enabling precise adjustment of the blade's horizontal position.

[0013] Furthermore, the insert section can be equipped with a pressure sensor with a measurement range of 0-5N, and a tension sensor with a measurement range of 0-10N can be installed on the lifting section to monitor the contact force, clamping force of the insert gripper, and insert position coordinates in real time during insert insertion, and transmit the data to the control system. When the clamping force is detected to be lower than 0.5N or the contact force exceeds 3N, the system automatically triggers an alarm and stops operation to ensure that optimal clamping and insertion safety are maintained throughout transportation and insertion. Furthermore, the insertion end of the insert has a wedge-shaped cutting edge with an included angle of 5°-20° and a cutting edge thickness of 10-20μm. The thickness of the insert body is 60μm-200μm; the length of the insert is 10mm-30mm; and the width of the insert is 10mm-20mm.

[0014] Preferably, the cutting edge of the insert must be free of burrs and micro-chips to avoid misjudgment of cracks or secondary damage to the wafer due to defects in the cutting edge during insertion.

[0015] Furthermore, the bonding wafer placement section includes a vacuum adsorption platform, a horizontal rotation device for the vacuum adsorption platform to rotate continuously in the horizontal direction at 360°, and a pitch adjustment device for the vacuum adsorption platform to rotate from -90° to +90° in the vertical direction.

[0016] Furthermore, the pitch adjustment device is located below the vacuum adsorption platform, and the pitch adjustment device includes a connected rotating shaft and a rotating frame, with the upper end of the rotating frame connected to the vacuum adsorption platform.

[0017] Furthermore, a vacuum generator is provided at the lower end of the rotating frame, and a channel is provided inside the rotating frame. One end of the channel is connected to the vacuum generator, and the other end of the channel is connected to the vacuum adsorption platform.

[0018] Furthermore, the rotating shaft is mounted on the support, the rotating frame is located inside the support, the lower end of the support is connected to the support frame, and the horizontal rotating device is located below the support frame to drive the support frame to perform horizontal rotation.

[0019] This application also provides a method for identifying the location of cracks in bonded wafers, comprising the following steps: (1) Place the bonding wafer on the bonding wafer placement part and fix it; (2) Locate the crack using the image sensor; (3) Insert the insert into the middle of the bonding surface of the wafer. If the crack is above the insert, the crack will be generated on the upper surface of the bonding wafer. Otherwise, the crack will be generated on the lower surface of the bonding wafer.

[0020] This application can bring the following beneficial effects: 1. This application utilizes image sensing technology to observe the wafer position in real time, facilitating the observation of wafer defects and accurately pinpointing the location of wafer cracks. Furthermore, by inserting the wafer into the crack location, the origin of the wafer crack can be found even more accurately, thereby assisting personnel in improving the process. The simple structure enables accurate location of bonding wafer cracks, improving wafer inspection efficiency and reducing false positives and false negatives caused by manual inspection.

[0021] 2. This application provides a gripper structure to grip the insert, and the contact surface between the gripper and the insert is provided with an anti-slip structure, which can both increase the friction between the gripper and the insert to prevent the blade from shifting and avoid scratching the surface of the insert during gripping.

[0022] 3. This application takes into account multiple factors (hardness, rigidity, chemical inertness, machinability, cost, observability, etc.) and optimizes the material of the insert, which is conducive to the insertion of the insert and the observation of cracks after insertion.

[0023] 4. The insert section of this application is provided with a vertical drive component for adjusting the height of the insert to align it with the wafer bonding interface, and a horizontal drive component for adjusting the horizontal distance between the insert and the wafer and controlling the insertion depth, so as to facilitate observation of the direction of crack generation and propagation path.

[0024] 5. The wedge-shaped cutting edge design of the insert in this application can gradually and smoothly enter the bonding interface, avoiding sudden stress concentration and accidental cracking of the wafer. It can more effectively and controllably separate the two wafers in local micro-regions. Compared with flat-head inserts, the initial contact between the wedge-shaped cutting edge and the wafer is a point or a very short line with greater pressure and easier insertion, but the total force is smaller and more precise.

[0025] 6. The design of the cutting edge angle ensures the accuracy of insertion and low stress; the micron-level cutting edge thickness minimizes compression and damage during insertion, maximizing the integrity of the sample.

[0026] 7. The design of various parameters of the insert in this application, such as the material, body thickness, insert length, width, cutting edge angle, shape, and cutting edge thickness, not only controls the insertion process and minimizes the impact on the wafer after insertion, but also takes into account the minimum number of cracks generated after insertion, the significant difference between the crack shape generated by the insert and the target crack morphology, so that they can be well distinguished in subsequent observation, and thus will not interfere with the target crack.

[0027] 8. The bonding wafer placement section of this application is equipped with a horizontal rotation device and a pitch adjustment device to achieve the purpose of observing the crack state from multiple angles. Attached Figure Description

[0028] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of a device for identifying the location of cracks in a bonded wafer in this application. Figure 2 A schematic diagram for confirming the location of cracks during die insertion into the bonding wafer; Figure 3 This is another schematic diagram of the device for identifying the location of bonding wafer cracks in this application; Figure 4 This is a schematic diagram of one structure of the bonding wafer placement section in this application.

[0029] in: 1. Light source; 100. Bonded wafer; 2. Bonded wafer placement section; 21. Vacuum adsorption platform; 22. Horizontal rotation device; 23. Rotation axis; 24. Rotation frame; 25. Vacuum generator; 251. Channel; 26. Bracket; 27. Support frame; 3. Insertion section; 31. Insertion; 32. Insertion clamping section; 33. Anti-slip structure; 34. Vertical drive assembly; 35. Horizontal drive assembly; 4. Light shielding section; 5. Image sensing section; 6. Display device. Detailed Implementation

[0030] To more clearly illustrate the overall concept of this application, a detailed explanation is provided below with reference to the accompanying drawings.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0032] Furthermore, it should be understood in the description of this application that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0034] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] In this application, unless otherwise expressly specified and limited, the "above" or "below" of the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0036] In one embodiment, an apparatus for identifying the location of a bonding wafer crack is provided, as shown in the attached diagram. Figure 1 Appendix Figure 2 As shown, the device structure includes: a bonding wafer placement section 2, a light source 1, an image sensing section 5, an insert section 3, and a light-shielding section 4. The light source 1 is disposed above the bonding wafer placement section 2, and the image sensing section 5 is disposed above the bonding wafer placement section 2 to transmit the image to the display device 6. The insert section 3 is disposed outside the bonding wafer placement section 2, and inserts 31 are inserted into the bonding wafer 100 to confirm the location of the crack. The bonding wafer placement section 2, the light source 1, the image sensing section 5, and the insert section 3 are all covered within the light-shielding section 4.

[0037] In practical use, the bonding wafer 100 to be tested is first placed face up on the bonding wafer placement part 2. Then, the detection light source 1 is turned on, and the bonding wafer placement part 2 is rotated. The image sensor 5 is used to observe the crack condition of the wafer on the display device 6. Once a crack is found, a picture is taken and the location is recorded. The wafer crack position is adjusted to the insertion part 3, and then the position of the insertion die 31 is adjusted up and down. The insertion die 31 is inserted at the crack position, between the bonding surfaces of the two wafers. The crack image is observed. If a crack image appears at the insertion position of the insertion die 31, it proves that the crack has grown on the front side of the wafer; otherwise, it has grown on the back side of the wafer.

[0038] In another embodiment, the insert portion 3 has been further structurally designed, such as... Figure 3 As shown, the insert part 3 includes an insert clamping part 32, which is a claw structure. The contact surface between the claw structure and the insert 31 is provided with an anti-slip structure 33. The anti-slip structure 33 is an array of hemispherical protrusions. The diameter of the hemispherical protrusions is 0.5-1mm, and the spacing between adjacent hemispherical protrusions is 1-2mm. The hemispherical protrusions are made of polyurethane material with a Shore hardness of 30-50A. The insert 31 is made of one or more composite materials selected from tungsten carbide, polycrystalline diamond, cubic boron nitride, zirconium oxide, and alumina.

[0039] In another embodiment, such as Figure 3 As shown, the insert part 3 also includes a vertical drive assembly 34 and a horizontal drive assembly 35; the stroke of the vertical drive assembly 34 is 50-150mm; the vertical drive assembly 34 is located below the insert clamping part 32 and is used to adjust the height of the insert clamping part 32. The specific drive structure can adopt a conventional lifting mechanism, such as a linear motor drive, a telescopic cylinder, etc.

[0040] The horizontal drive assembly 35 can be positioned above the vertical drive assembly 34, using a telescopic structure such as a cylinder or linear motor to drive the telescopic movement of the insert clamping part, while the vertical drive assembly drives the lifting and lowering movement of the overall structure above from below.

[0041] like Figure 3 As shown, the horizontal drive component 35 can be set outside the vertical drive component, driving the insert part 3 to perform reciprocating motion in the horizontal direction. A slide structure can be set at the lower end of the insert part 3. The horizontal drive component 35 is driven by a linear motor with a stroke of 10-30μm.

[0042] In another embodiment, the insert 31 is further structurally designed, with the insertion end of the insert 31 having a wedge-shaped cutting edge with an included angle of 5°-20° and a cutting edge thickness of 10-20μm; the body thickness of the insert 31 is 60μm-200μm; the length of the insert 31 is 10mm-30mm; and the width of the insert 31 is 10mm-20mm.

[0043] In practical applications, for the bonded wafer 100 formed after bonding lithium niobate and silicon carbide wafers, insert 31 is inserted at the crack location. Insert 31 is inserted between the bonding surfaces of the two wafers. Observing the crack image, the crack generated by the insertion of insert 31 in this application is different in shape from the crack caused by thermal stress (target crack). The crack generated after bonding and annealing of silicon carbide and lithium niobate is a straight crack that runs through the wafer surface; the crack generated by the insertion of insert 31 in this application is a short curved crack. The two crack morphologies are easily distinguishable by the naked eye.

[0044] In another embodiment, the bonding wafer placement portion 2 is further structurally designed, such as... Figure 4 As shown, the bonding wafer placement section 2 includes a vacuum adsorption platform 21, a horizontal rotation device 22 for continuous 360° horizontal rotation of the vacuum adsorption platform 21, and a pitch adjustment device for achieving -90° to +90° vertical rotation of the vacuum adsorption platform 21. The pitch adjustment device is located below the vacuum adsorption platform 21 and includes a connected rotating shaft 23 and a rotating frame 24. The upper end of the rotating frame 24 is connected to the vacuum adsorption platform 21. A vacuum generator 25 is located at the lower end of the rotating frame 24, and a channel 251 is provided inside the rotating frame 24. One end of the channel 251 is connected to the vacuum generator 25, and the other end is connected to the vacuum adsorption platform 21. The rotating shaft 23 is mounted on a support 26, and the rotating frame 24 is located inside the support 26. The lower end of the support 26 is connected to a support frame 27. The horizontal rotation device 22 is located below the support frame 27, driving the support frame 27 to rotate horizontally.

[0045] In use, the bonding wafer placement unit 2 places the bonding wafer 100 on the vacuum adsorption platform 21. Due to the structure of the vacuum generator 25 and the channel 251, the bonding wafer 100 is adsorbed and fixed on the platform. If the wafer position needs to be adjusted during wafer crack observation, the horizontal rotation device 22 can be used to drive the support frame 27 to rotate horizontally, thereby driving the support 26 and the vacuum adsorption platform 21 to rotate horizontally. If the tilt angle of the vacuum adsorption platform 21 needs to be adjusted vertically, the forward or reverse rotation of the rotating shaft 23 will drive the vacuum adsorption platform 21 on the rotating frame 24 to tilt or lower, changing the tilt angle. A motor can be connected to the outer end of the rotating shaft 23, and the motor controls its rotation direction and angle.

[0046] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0047] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. An apparatus for confirming the location of cracks in bonded wafers, characterized in that, include: Bonding wafer placement section A light source is positioned above the bonding wafer placement area. An image sensing unit is disposed above the bonding wafer placement unit to transmit images to a display device; An insert portion is provided on the outside of the bonding wafer placement portion, and an insert portion is inserted into the bonding wafer to confirm the location of the crack. The light-shielding section covers the bonding wafer placement section, the light source, the image sensing section, and the insertion section.

2. The apparatus for confirming the location of a bonding wafer crack according to claim 1, characterized in that: The insert part includes an insert clamping part, which is a claw structure. The contact surface between the claw structure and the insert is provided with an anti-slip structure. The anti-slip structure is an array of hemispherical protrusions with a diameter of 0.5-1mm and a spacing of 1-2mm between adjacent hemispherical protrusions. The hemispherical protrusions are made of polyurethane material with a Shore hardness of 30-50A.

3. The apparatus for confirming the location of a bonding wafer crack according to claim 1, characterized in that: The insert is made of one or more composite materials selected from tungsten carbide, polycrystalline diamond, cubic boron nitride, zirconium oxide, and aluminum oxide.

4. The apparatus for confirming the location of a bonding wafer crack according to claim 2, characterized in that: The insert part further includes a vertical drive assembly for lifting and lowering the insert clamping part, and a horizontal drive assembly for horizontal linear reciprocating motion of the insert clamping part; the stroke of the vertical drive assembly is 50-150mm; the stroke of the horizontal drive assembly is 10-30μm.

5. The apparatus for confirming the location of a bonding wafer crack according to claim 1, characterized in that: The insertion end of the insert is provided with a wedge-shaped cutting edge, the included angle of the cutting edge is 5°-20°, and the thickness of the cutting edge is 10-20μm; The thickness of the insert body is 60-200μm; the length of the insert is 10-30mm; and the width of the insert is 10-20mm.

6. The apparatus for confirming the location of a bonding wafer crack according to claim 1, characterized in that: The bonding wafer placement section includes a vacuum adsorption platform, a horizontal rotation device for the vacuum adsorption platform to rotate continuously 360° in the horizontal direction, and a pitch adjustment device for the vacuum adsorption platform to rotate from -90° to +90° in the vertical direction.

7. The apparatus for confirming the location of a bonding wafer crack according to claim 6, characterized in that: The pitch adjustment device is located below the vacuum adsorption platform. The pitch adjustment device includes a connected rotating shaft and a rotating frame, and the upper end of the rotating frame is connected to the vacuum adsorption platform.

8. The apparatus for confirming the location of a bonding wafer crack according to claim 7, characterized in that: A vacuum generator is installed at the lower end of the rotating frame, and a channel is provided inside the rotating frame. One end of the channel is connected to the vacuum generator, and the other end of the channel is connected to the vacuum adsorption platform.

9. The apparatus for confirming the location of a bonding wafer crack according to claim 7, characterized in that: The rotating shaft is mounted on the support, the rotating frame is located inside the support, the lower end of the support is connected to the support frame, and the horizontal rotating device is located below the support frame to drive the support frame to perform horizontal rotation.

10. A method for confirming the location of a bonded wafer crack, characterized in that, Includes the following steps: (1) Place the bonding wafer on the bonding wafer placement part and fix it; (2) Locate the crack using the image sensor; (3) Insert the insert into the middle of the bonding surface of the wafer. If the crack is above the insert, the crack will be generated on the upper surface of the bonding wafer. Otherwise, the crack will be generated on the lower surface of the bonding wafer.

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