Wafer bonding device

Abstract

The utility model provides a wafer bonding device which comprises a lower pressing plate and a wafer clamping jig, at least three elastic supporting jigs are arranged on the periphery of the lower pressing plate, and the top ends of the elastic supporting jigs are higher than the upper surface of the lower pressing plate; a wafer to be bonded is carried on the wafer clamping jig, the wafer clamping jig comprises at least two layers of wafers which are sequentially arranged at intervals, the wafer clamping jig and the wafer to be bonded on the wafer clamping jig are arranged on the elastic supporting jig together, and the bounce of the elastic supporting jig is equal to the total gravity of the wafer clamping jig and the wafer to be bonded. A gap is reserved between the lower pressing plate and the wafer to be bonded; the device further comprises an upper pressing plate, the upper pressing plate is located over the lower pressing plate and connected with the driving mechanism, and under the action of the driving mechanism, the upper pressing plate is close to or away from the lower pressing plate. When the wafer is subjected to the pressure of the upper pressing plate, the elastic supporting jig can properly deform, so that the pressure is absorbed and dispersed, the wafer is prevented from being broken due to overlarge pressure, and the height of the supporting structure does not need to be frequently and manually adjusted to compensate the thickness difference of the pressing plate.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor technology, and in particular relates to a wafer bonding device. Background Technology

[0002] In the field of material bonding technology, the application of different bonding methods is often limited by material compatibility. For example, during the bonding process of materials such as silicon, glass, and metals, contaminants may be generated and migrated due to chemical reactions or physical interactions. Therefore, in production practice, to ensure material compatibility and process stability, it is necessary to frequently change the upper and lower bonding plates on the bonding machine for different types of bonded products. However, this practice also brings a new problem: due to manufacturing tolerances, the thickness of the bonding plates leaving the factory generally varies by about 0.1 mm.

[0003] In wafer bonding processes, the support structure of the wafer clamping fixture is a critical component. This support structure adjusts its height mechanically to precisely control the distance between the wafer and the lower platen before bonding. This precise control of the distance is crucial: if the distance is too large, the wafer may break under pressure; if the distance is too small, the wafer may prematurely contact the lower platen, interfering with bonding accuracy. Considering the inconsistency in the thickness of the bonding plates, if the height of the support structure remains fixed, the actual distance between the wafer and the platen will change during the process, increasing the risk of wafer breakage or compromised bonding accuracy. Manually adjusting the support structure height each time to compensate for the platen thickness variation is not only cumbersome but also extremely difficult to achieve adjustments with a precision of 0.1 millimeters. Utility Model Content

[0004] In order to solve all or part of the problems of the prior art, this utility model provides a wafer bonding device. By introducing an elastic support fixture, it can undergo appropriate deformation during the bonding process, effectively preventing the wafer from cracking due to excessive pressure. It also solves the problem of controlling the distance between the wafer and the bonding plate due to the difference in the thickness of the bonding plate.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A wafer bonding apparatus includes a lower pressure plate and a wafer clamping fixture. At least three elastic support fixtures are arranged around the periphery of the lower pressure plate, with their tops extending above the upper surface of the lower pressure plate. The wafer clamping fixture carries a wafer to be bonded, comprising at least two layers of wafers placed at intervals. The wafer clamping fixture and the wafer to be bonded are placed together on the elastic support fixtures. The rebound force of the elastic support fixtures is equal to the total weight of the wafer clamping fixture and the wafer to be bonded, creating a gap between the lower pressure plate and the wafer to be bonded. The apparatus also includes an upper pressure plate located directly above the lower pressure plate and connected to a driving mechanism. Under the action of the driving mechanism, the upper pressure plate moves closer to or further away from the lower pressure plate. By setting at least three elastic support fixtures with their tops higher than the upper surface of the lower pressure plate around the perimeter, the wafer clamping fixture carrying the wafer to be bonded is effectively supported. The rebound force of the elastic support fixture is exactly equal to the total weight of the wafer clamping fixture and the wafer to be bonded, leaving a gap between the lower pressure plate and the wafer to be bonded, thus avoiding direct pressure before bonding. When the wafer is subjected to pressure from the upper pressure plate, the elastic support fixture can deform appropriately to absorb and disperse the pressure, preventing the wafer from breaking due to excessive pressure. At the same time, it avoids the cumbersome operation of frequently manually adjusting the height of the support structure to compensate for the thickness difference of the pressure plate in traditional processes.

[0007] The elastic support fixture includes a fixed part and a telescopic part. The fixed part is installed around the periphery of the lower pressure plate and has an elastic element disposed inside it. One end of the telescopic part is connected to the elastic element, and the other end supports the wafer clamping fixture. The rebound force of the elastic element in the initial state is equal to the total weight of the wafer clamping fixture and the wafer to be bonded. The design of the telescopic part allows the elastic support fixture to adjust in real time according to the force applied when the upper pressure plate applies pressure for wafer bonding, thereby effectively solving the problem that the first layer of wafer is prone to breakage due to pressure in traditional purely mechanical support structures.

[0008] The wafer clamping fixture is designed in a ring shape, with through holes on its surface that correspond one-to-one with the telescopic parts. A fixing block is positioned above each through hole, constraining the telescopic part within the corresponding through hole. The wafer to be bonded includes a first-layer wafer and a second-layer wafer. The matching design of the through holes and telescopic parts allows the wafer clamping fixture to be stably placed on the elastic support fixture, while the presence of the fixing blocks prevents the telescopic parts from excessively deforming or disengaging from the through holes under pressure.

[0009] The inner ring of the wafer clamping fixture has multiple vacuum suction structures arranged radially. Matching openings are formed on the lower pressure plate at positions corresponding to these vacuum suction structures. When the wafer clamping fixture is placed on the elastic support fixture, the vacuum suction structures are embedded into these openings. This matching design between the vacuum suction structures and the lower pressure plate openings not only enhances the connection stability between the wafer clamping fixture and the lower pressure plate but also allows for a more uniform pressure distribution on the wafer during bonding, further improving the quality of wafer bonding.

[0010] The first wafer layer is placed on the upper surface of the vacuum suction structure, which has vacuum suction holes on its surface. These holes are used by a vacuum generator to hold the first wafer layer in place. This effectively prevents the wafer from shifting or falling off when pressure is applied or other operations are performed.

[0011] The wafer clamping fixture has at least three clamping mechanisms on its ring. Each clamping mechanism includes a fixing component and a spacer component. The spacer component supports the second-layer wafer, and the fixing component clamps and secures the second-layer wafer. The spacer component ensures a certain gap between the first-layer and second-layer wafers before bonding, which facilitates vacuuming and reduces the likelihood of air bubbles forming during bonding.

[0012] The spacer assembly includes a linear drive component and a spacer plate disposed on the linear drive component. One end of the spacer plate is connected to the linear drive component, and the other end is used to support the second layer wafer, thereby maintaining a certain distance between the first layer wafer and the second layer wafer. The linear drive component drives the spacer plate to perform linear reciprocating motion along the center direction of the wafer, causing the spacer plate to insert or withdraw between the first layer wafer and the second layer wafer. This achieves stable support for the second layer wafer.

[0013] The spacer supporting the second wafer can be a single-layer or multi-layer structure; the spacer is made of a thin, elastic metal sheet; the multi-layer spacer is designed with multiple steps at one end, each step capable of supporting a single wafer. When supporting the second wafer, the spacer can be designed as a single-layer structure to meet basic support requirements, or as a multi-layer structure to provide more flexible and diverse support options.

[0014] The clamping assembly includes an opening / closing drive component and grippers disposed on the opening / closing drive component. The opening / closing drive component drives the grippers to press downwards or tilt upwards. When pressing downwards, the free end of the grippers presses against the second layer wafer; when tilting upwards, the free end of the grippers moves upwards away from the second layer wafer. This achieves stable clamping of the second layer wafer.

[0015] This utility model has at least the following beneficial effects:

[0016] 1) In traditional wafer bonding processes, the inconsistent thickness of the bonding pads often makes it difficult to precisely control the actual distance between the wafer and the pad during the process, increasing the risk of wafer breakage or damage to bonding precision. This invention, through the ingenious design of an elastic support fixture, achieves automatic adaptation and precise control of the wafer-to-pad distance. Regardless of changes in the thickness of the bonding pad, the elastic support fixture can maintain a stable gap between the wafer and the pad through its deformation capacity, effectively solving the distance control problem caused by differences in bonding pad thickness.

[0017] 2) The rebound force of the elastic support fixture is exactly equal to the total weight of the wafer clamping fixture and the wafer to be bonded, leaving a gap between the pressure plate and the wafer to be bonded. This avoids direct pressure before bonding, thereby reducing the risk of wafer damage. Furthermore, the telescopic design of the elastic support fixture allows for real-time adjustment according to the stress conditions, effectively solving the problem of wafers easily breaking under pressure in traditional purely mechanical support structures, further improving the accuracy and stability of wafer bonding.

[0018] 3) The wafer clamping fixture of this invention also includes a clamping mechanism, comprising a fixing component and a spacer component, for clamping and fixing the second-layer wafer and ensuring a certain gap between the first-layer wafer and the second-layer wafer before bonding. The design of the spacer component facilitates vacuuming operations, reducing air bubbles that may occur during bonding, thereby improving the quality of wafer bonding. Simultaneously, the opening and closing drive component of the clamping component drives the jaws to press downwards or tilt upwards, achieving stable clamping of the second-layer wafer and further improving the stability of wafer bonding. Furthermore, the multi-stage stepped design of the spacer provides a more flexible and diverse support solution for the wafer. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific 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.

[0020] Figure 1 This is a schematic cross-sectional view of an elastic support fixture in a wafer bonding device according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic cross-sectional view of a wafer clamping fixture in a wafer bonding apparatus according to an embodiment of the present invention.

[0022] Figure 3This is a schematic diagram of the structure of a wafer clamping fixture for a wafer bonding device according to an embodiment of the present invention.

[0023] Figure 4 Provided for the embodiments of this utility model Figure 3 A schematic diagram of the clamping mechanism.

[0024] Reference numerals: 1-lower pressure plate; 2-wafer clamping fixture; 21-through hole; 22-fixed stop; 23-vacuum suction structure; 24-clamping mechanism; 241-fixing component; 2411-opening and closing drive component; 2412-gripper; 242-partition component; 2421-linear drive component; 2422-partition plate; 3-elastic support fixture; 301-fixing part; 302-telescopic part; 303-elastic element; 4-first layer wafer; 5-second layer wafer; 6-upper pressure plate. Detailed Implementation

[0025] The technical solutions in specific embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0026] The implementation of this utility model will be described in detail below with reference to specific embodiments.

[0027] In this embodiment of the utility model, in conjunction with reference to the reference Figures 1-4 As shown, a wafer bonding apparatus is provided. The apparatus mainly consists of an upper pressure plate 6, a lower pressure plate 1, and a wafer clamping fixture 2. Three elastic support fixtures 3 are provided on the outer edge of the lower pressure plate 1, with their tops designed to be higher than the upper surface of the lower pressure plate 1 to ensure stable support of the wafers during the bonding process. The upper pressure plate 6 is located directly above the lower pressure plate 1 and is connected to it via a drive mechanism. Under the precise control of the drive mechanism, the upper pressure plate 6 can smoothly move closer to or further away from the lower pressure plate 1 to meet different wafer bonding requirements. The wafer clamping fixture 2, as a key component for supporting the wafers to be bonded, has at least two layers of wafers placed on it at intervals, forming a wafer assembly to be bonded. This assembly, along with the wafer clamping fixture 2 itself, is placed on the elastic support fixtures 3. Notably, the rebound force provided by these elastic support fixtures 3 is precisely designed to be equal to the total weight of the wafer clamping fixture 2 and the wafer assembly to be bonded. This design not only ensures stable support for the wafer before bonding, but also cleverly leaves an appropriate gap between the pressure plate 1 and the wafer to be bonded, thereby effectively preventing the wafer from contacting the pressure plate 1 prematurely during the bonding process, which would interfere with the bonding accuracy.

[0028] The elastic support fixture 3 mainly consists of a fixed part 301 and a telescopic part 302. The fixed part 301 is installed around the periphery of the lower pressure plate 1 and contains high-performance elastic elements 303, which possess excellent resilience and durability. One end of the telescopic part 302 is connected to the elastic element 303, and the other end is used to support the wafer clamping fixture 2 and the wafer to be bonded on it. Crucially, in its initial state without external force, the elastic element 303 is exactly equal to the total weight of the wafer clamping fixture 2 and the wafer to be bonded placed on it.

[0029] The wafer clamping fixture 2 is circular in shape to ensure uniform support for the wafers to be bonded. Through holes 21, corresponding to and matching the telescopic parts 302, are formed on the surface of the wafer clamping fixture 2. Fixing blocks 22 are positioned above these through holes 21, constraining the telescopic parts 302 within the corresponding through holes 21. This effectively prevents the wafers from shaking or shifting during the bonding process, ensuring the accuracy and stability of the wafer bonding. In this embodiment, the wafers to be bonded specifically include a first layer wafer 4 and a second layer wafer 5. These two layers of wafers are placed sequentially on the wafer clamping fixture 2. A certain distance is maintained between the bottom wafer and the lower pressure plate 1 by the support of the elastic support fixture 3.

[0030] The inner ring of the wafer clamping fixture 2 is equipped with three precise vacuum suction structures 23 arranged radially. These structures are not only rationally laid out but also perfectly matched to the outer contour of the wafer, thereby achieving omnidirectional and uniform adsorption of the wafer. To cooperate with these vacuum suction structures 23, corresponding openings are made on the lower pressure plate 1. When the wafer clamping fixture 2 is securely placed on the elastic support fixture 3, these vacuum suction structures 23 can be accurately embedded into the openings, forming a stable adsorption channel. The first layer of wafer 4 is placed on the upper surface of the vacuum suction structure 23. It is worth noting that the surface of the vacuum suction structure 23 is carefully designed with multiple vacuum suction holes. When the vacuum generator connected to the vacuum suction structure 23 is activated, these vacuum suction holes can generate adsorption force to adsorb the first layer of wafer 4 onto the upper surface of the vacuum suction structure 23, thereby avoiding any slight displacement or shaking of the wafer during the bonding process and providing a strong guarantee for the precise bonding of the wafer.

[0031] The wafer clamping fixture 2 is also equipped with three sets of clamping mechanisms 24 on its ring. Each clamping mechanism 24 includes a fixing component 241 and a spacer component 242. Through their coordinated operation, they jointly complete the precise support and fixation of the second-layer wafer 5. The spacer component 242 includes a linear drive component 2421 and a spacer plate 2422. One end of the spacer plate 2422 is connected to the linear drive component 2421, and the other end is used to support the second-layer wafer 5, ensuring that a certain distance is maintained between the first-layer wafer 4 and the second-layer wafer 5. This is crucial for the precise alignment and bonding of the wafers. The linear drive component 2421 can drive the spacer plate 2422 to perform precise linear reciprocating motion along the center direction of the wafer, so that the spacer plate 2422 can be inserted or removed between the first-layer wafer 4 and the second-layer wafer 5 when needed. In this embodiment, the end of the spacer plate 2422 that supports the second-layer wafer 5 adopts a single-layer structure to simplify the structure and reduce costs. In other specific embodiments, to meet the requirements of multilayer wafer bonding, one end of the spacer 2422 can also be designed as a multilayer structure, particularly a multi-step structure, where each step can independently and stably support a wafer. This design greatly expands the application range of the wafer clamping fixture 2. Furthermore, the spacer 2422 is made of high-quality elastic metal sheet, ensuring not only sufficient rigidity and stability but also a certain degree of elasticity to accommodate slight differences in wafer sizes. The clamping assembly is responsible for fixing and releasing the second layer wafer 5, integrating an opening / closing drive component 2411 and a gripper 2412. The opening / closing drive component 2411 drives the gripper 2412 to perform downward pressing or upward tilting actions. When the gripper 2412 presses down, its free end can tightly adhere to and press the second wafer 5, ensuring the absolute stability of the wafer during the bonding process; while when the gripper 2412 tilts up, its free end can quickly and smoothly leave the second wafer 5, facilitating the removal of the wafer or the next operation.

[0032] This invention introduces an elastic support fixture 3, replacing the traditional mechanical height-adjustable support structure. This simplifies the installation and debugging process of the wafer bonding device and improves its flexibility and adjustability. The elastic support fixture 3 is ingeniously designed; its top is slightly higher than the upper surface of the lower pressure plate 1. The rebound force provided by the elastic support fixture 3 is precisely designed to be equal to the total weight of the wafer clamping fixture 2 and the wafer to be bonded. This leaves an appropriate gap between the lower pressure plate 1 and the wafer to be bonded, ensuring that the wafer is in a stable suspended state before bonding. This effectively prevents the wafer from prematurely contacting the lower pressure plate 1 during bonding, thus interfering with bonding accuracy. Furthermore, the introduction of the elastic support fixture 3 allows the elastic element 303 of the elastic support fixture 3 to contract when pressure is applied by the upper pressure plate 6, ensuring a perfect fit between the first layer wafer 4 and the lower pressure plate 1, thereby ensuring the quality and efficiency of wafer bonding.

[0033] This invention innovatively introduces an elastic support fixture 3, replacing the traditional mechanical height-adjustable support structure. This not only greatly simplifies the installation and debugging process of the wafer bonding device but also significantly improves the device's flexibility and adjustability. The elastic support fixture 3 is ingeniously designed; its top is carefully positioned slightly above the upper surface of the lower pressure plate 1. Furthermore, the rebound force provided by the elastic support fixture 3 is meticulously calculated and designed to ensure that it equals the total weight of the wafer clamping fixture 2 and the assembly of wafers to be bonded supported on it. This design allows for a certain gap between the lower pressure plate 1 and the wafers to be bonded, enabling the wafers to maintain a stable suspended state before the bonding operation begins. This effectively avoids precision interference problems that might occur if the wafers prematurely contact the lower pressure plate 1 during the bonding process. In addition, the introduction of the elastic support fixture 3 also gives the wafer bonding process greater controllability. When the upper pressure plate 6 begins to apply pressure, the elastic element 303 in the elastic support fixture 3 can flexibly contract. This characteristic ensures that the first layer wafer 4 can achieve perfect bonding under the pressure of the lower pressure plate 1, without damaging the wafer due to excessive pressure, thus effectively guaranteeing the quality and efficiency of wafer bonding. This design not only reflects a profound understanding of wafer bonding technology, but also demonstrates the outstanding contribution of this invention to improving the technological level of the semiconductor manufacturing field.

[0034] It should be noted that, for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the scope of protection of the claims of this utility model.

Claims

1. A wafer bonding apparatus, characterized in that, The device includes a lower pressure plate (1) and a wafer clamping fixture (2). At least three elastic support fixtures (3) are provided around the periphery of the lower pressure plate (1), with their tops higher than the upper surface of the lower pressure plate (1). The wafer clamping fixture (2) carries a wafer to be bonded, including at least two layers of wafers placed at intervals. The wafer clamping fixture (2) and the wafer to be bonded thereon are placed on the elastic support fixtures (3). The rebound force of the elastic support fixtures (3) is equal to the total weight of the wafer clamping fixture (2) and the wafer to be bonded, so that there is a gap between the lower pressure plate (1) and the wafer to be bonded. The device also includes an upper pressure plate (6), which is located directly above the lower pressure plate (1) and connected to a driving mechanism. Under the action of the driving mechanism, the upper pressure plate (6) moves closer to or away from the lower pressure plate (1).

2. The apparatus according to claim 1, characterized in that, The elastic support fixture (3) includes a fixing part (301) and a telescopic part (302). The fixing part (301) is installed on the periphery of the lower pressure plate (1) and has an elastic element (303) inside it. One end of the telescopic part (302) is connected to the elastic element (303) and the other end supports the wafer clamping fixture (2). The rebound force of the elastic element (303) in the initial state is equal to the total weight of the wafer clamping fixture (2) and the wafer to be bonded.

3. The apparatus according to claim 2, characterized in that, The wafer clamping fixture (2) is designed in the shape of a ring, and its surface is provided with through holes (21) that correspond one-to-one with the telescopic part (302). A fixing block (22) is provided above the through hole (21), and the fixing block (22) constrains the telescopic part (302) inside the corresponding through hole (21). The wafer to be bonded includes a first layer wafer (4) and a second layer wafer (5).

4. The apparatus according to claim 3, characterized in that, The inner ring of the wafer clamping fixture (2) is provided with a plurality of vacuum suction structures (23) in the radial direction. The lower pressure plate (1) has a matching opening at the position corresponding to the vacuum suction structure (23). When the wafer clamping fixture (2) is placed on the elastic support fixture (3), the vacuum suction structure (23) is embedded in the opening.

5. The apparatus according to claim 4, characterized in that, The first layer wafer (4) is placed on the upper surface of the vacuum suction structure (23), and the surface of the vacuum suction structure (23) is provided with vacuum suction holes. The vacuum suction holes are used to adsorb and fix the first layer wafer (4) by a vacuum generator.

6. The apparatus according to claim 3, characterized in that, The wafer clamping fixture (2) has at least three clamping mechanisms (24) on its ring. The clamping mechanism (24) includes a fixing component (241) and a partition component (242). The partition component (242) is used to support the second layer wafer (5), and the fixing component (241) is used to clamp and fix the second layer wafer (5).

7. The apparatus according to claim 6, characterized in that, The partition assembly (242) includes a linear drive component (2421) and a partition plate (2422) disposed on the linear drive component (2421). One end of the partition plate (2422) is connected to the linear drive component (2421), and the other end is used to support the second layer wafer (5), so that a certain distance is maintained between the first layer wafer (4) and the second layer wafer (5). The linear drive component (2421) drives the partition plate (2422) to perform linear reciprocating motion along the center direction of the wafer, so that the partition plate (2422) is inserted or removed between the first layer wafer (4) and the second layer wafer (5).

8. The apparatus according to claim 7, characterized in that, The partition plate (2422) supporting the second layer wafer (5) has a single-layer structure or a multi-layer structure; the partition plate (2422) is made of a metal elastic sheet.

9. The apparatus according to claim 8, characterized in that, The multi-layered baffle (2422) is designed with a multi-step shape at one end, and each step can support a wafer independently.

10. The apparatus according to claim 6, characterized in that, The fixing component (241) includes an opening and closing driving component (2411) and a gripper (2412) disposed on the opening and closing driving component (2411). The opening and closing driving component (2411) drives the gripper (2412) to press down or tilt up. When pressed down, the free end of the gripper (2412) presses against the second layer wafer (5). When tilted up, the free end of the gripper (2412) moves upward away from the second layer wafer (5).

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