Wafer bonding tool and bonding apparatus

Abstract

The utility model discloses a kind of wafer bonding tool and bonding device, it is related to the technical field of semiconductor material processing.Wafer bonding tool includes support piece and positioning assembly, support piece is equipped with bearing part, bearing part has bearing side and non-bearing side, bearing side is used to bear wafer pair, and the projection of wafer pair is completely located in bearing plane, non-bearing side is used to receive external force.Positioning assembly is laid in the circumference of bearing part, for positioning wafer pair in bearing side.Pre-alignment to wafer pair is realized before bonding operation, when pressure is applied to non-bearing side, the entire bonding surface of wafer pair can be extruded, so that the stress of wafer pair is uniform, ensure that the bonding interface of two wafers is combined closely, and then the bonding quality is guaranteed, and product yield is improved.

Description

Technical Field

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

[0002] In the field of semiconductor material processing, wafer bonding technology is a key process for realizing three-dimensional integration, manufacturing microelectromechanical systems (MEMS), and advanced packaging. One of the core steps of this process is to tightly and permanently bond two wafers (i.e., a "wafer pair") together under specific conditions. The wafer pair holding fixture plays a crucial role in this process, and its core function is to precisely hold and fix the two wafers in their relative positional relationship, as well as to transfer them between different process stages.

[0003] Currently, the wafer pairing fixtures commonly used in the industry are mostly ring-shaped structures. For example... Figure 1 and Figure 2 As shown, this type of tooling typically has an inwardly protruding support boss 102 on the inner wall of its annular ring 101. The outer edge of the wafer pair 200 overlaps the support boss 102, relying on the support boss 102 to provide support force, thereby achieving positioning and attitude maintenance within the tooling. However, this design based on the annular structure and support boss 102 exposes a significant technical defect in the actual bonding process: when the upper or lower pressure head is used to apply bonding pressure to the wafer through the hollow area of ​​the tooling, due to the presence of the support boss 102, the local area where the wafer overlaps the support boss 102 cannot be directly pressured by the pressure head, resulting in extremely uneven pressure distribution on the entire bonding surface; areas with insufficient pressure are prone to forming loose bonding interfaces, producing micro-gaps or trapped air bubbles, leading to a decrease in product yield. Utility Model Content

[0004] The purpose of this invention is to provide a wafer bonding fixture and bonding device that can ensure uniform stress on the bonding surface of the wafer during wafer bonding, thereby improving bonding quality and ensuring product yield.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] Wafer bonding fixtures, including:

[0007] The support member has a load-bearing portion, which has a load-bearing side and a non-load-bearing side, and the projection of the wafer pair is completely located within the load-bearing plane; the non-load-bearing side is used to receive external forces.

[0008] A positioning component is arranged circumferentially on the support portion to position the wafer pair on the support side.

[0009] As an optional embodiment of the wafer bonding fixture, the support member includes a support ring and a carrier plate disposed within the support ring, wherein the carrier portion is the carrier plate.

[0010] As an optional embodiment of the wafer bonding fixture, the carrier plate is a silicon carbide plate.

[0011] As an alternative to the wafer bonding fixture, the carrier plate is fixed to the support ring by fixing components distributed along its circumference.

[0012] As an optional embodiment of the wafer bonding fixture, the fixing component includes a limiting pin, the support ring is provided with a limiting hole that extends radially through it, the carrier plate is provided with a limiting groove in the circumferential direction, and the limiting pin passes through the limiting hole and is inserted into the limiting groove.

[0013] As an optional solution for the wafer bonding fixture, the fixing component further includes a fastening screw, and the support ring is also provided with a threaded hole communicating with the limiting hole. The fastening screw is screwed into the threaded hole and abuts against the limiting pin to lock the limiting pin.

[0014] As an optional embodiment of the wafer bonding fixture, the limiting hole includes a connected large-diameter hole and a small-diameter hole, and the limiting pin includes a connected large-diameter pin and a small-diameter pin, with the large-diameter pin located inside the large-diameter hole and the small-diameter pin inserted into the limiting groove;

[0015] The fastening screw abuts against the stepped surfaces of the large-diameter pin and the small-diameter pin.

[0016] As an optional embodiment of the wafer bonding fixture, the positioning component includes a positioning disk and a positioning pin. The positioning disk is located circumferentially on the support portion, and the positioning pin is retractable on the positioning disk so that the wafer pair can be placed on the support side and abut against the wafer pair.

[0017] As an optional embodiment of the wafer bonding fixture, the wafer bonding fixture further includes a spacer pressing component, which is arranged circumferentially on the support portion and alternately arranged with the positioning component.

[0018] As an optional embodiment of the wafer bonding fixture, the non-load-bearing side is used to contact the press, and the area of ​​the non-load-bearing side is the same as the area of ​​the pressing surface of the press.

[0019] A bonding apparatus comprising a wafer bonding fixture as described in any of the above embodiments.

[0020] The beneficial effects of this utility model are:

[0021] The wafer bonding fixture provided by this utility model includes a support and a positioning assembly. The support has a bearing portion, which has a bearing side and a non-bearing side. The bearing side is used to support a wafer pair. When the wafer pair is placed on the bearing side, the projection of the wafer pair is completely located within the bearing side. The wafer pair is positioned on the bearing side by a circumferential positioning assembly arranged on the bearing plane, achieving pre-alignment of the wafer pair before the bonding operation. When an external force is applied to the non-bearing side, the entire bonding surface of the wafer pair can be compressed, resulting in uniform force on the wafer pair and ensuring a tight bond at the bonding interface of the two wafers. This, in turn, ensures bonding quality and improves product yield.

[0022] The bonding apparatus provided by this utility model includes the wafer bonding fixture described above, which can ensure the pre-alignment of wafer pairs before bonding and ensure that the entire bonding surface of the wafer pairs is subjected to uniform force and the bonding interface is tightly bonded during bonding, thereby ensuring bonding quality and improving product yield. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a wafer bonding tooling in the prior art;

[0024] Figure 2 This is a schematic diagram of the structure of a wafer bonding fixture that fixes a wafer pair in the prior art;

[0025] Figure 3 This is a schematic diagram of the structure of the wafer bonding fixture for fixing wafer pairs provided in a specific embodiment of this utility model;

[0026] Figure 4 This is a cross-sectional view of the cooperation between the support plate and the fixing component provided in a specific embodiment of this utility model;

[0027] Figure 5 yes Figure 4 A magnified view of a section at point A in the middle;

[0028] Figure 6 This is a cross-sectional view of the wafer bonding fixture used in a specific embodiment of the present invention to fix the wafer pair to be bonded.

[0029] In the picture:

[0030] 101. Circular ring; 102. Bearing boss;

[0031] 200. Wafer pair; 201. Facet;

[0032] 1. Support ring; 11. Threaded hole;

[0033] 2. Load-bearing plate; 21. Load-bearing side; 22. Limiting groove; 23. Non-load-bearing side;

[0034] 3. Positioning component; 31. Positioning disc; 32. Positioning pin;

[0035] 41. Limit pin; 42. Fastening screw;

[0036] 5. Interval pressing component. Detailed Implementation

[0037] To make the technical problem solved by this utility model, the technical solution adopted, and the technical effect achieved clearer, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0038] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" 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 or an electrical 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 utility model based on the specific circumstances.

[0039] This embodiment provides a wafer bonding fixture for pre-aligning two wafers in a wafer pair, making the two wafers concentric with the support; and for fixing the wafer pair to ensure that the aligned wafer pair is transferred to the next process step without relative displacement.

[0040] like Figures 3-6 As shown, the wafer bonding fixture provided in this embodiment includes a support and a positioning assembly 3. The support has a bearing portion, which has a bearing side 21 and a non-bearing side 23. The bearing side 21 is used to bear the wafer pair 200, and the projection of the wafer pair 200 is completely located within the bearing side 21. The positioning assembly 3 is evenly distributed around the bearing portion to position the wafer pair 200 on the bearing side 21, achieving pre-alignment of the wafer pair 200 before the bonding operation. When an external force is applied to the non-bearing side 23, the entire bonding surface of the wafer pair 200 can be squeezed, making the wafer pair 200 subject to uniform force, ensuring a tight bond at the bonding interface of the two wafers, thereby ensuring bonding quality and improving product yield.

[0041] In one embodiment, the non-load-bearing side 23 is used to contact the press, and the area of ​​the non-load-bearing side 23 is the same as the area of ​​the pressing surface of the press. During the bonding of wafer pairs 200, it is ensured that the pressing surface and the non-load-bearing side 23 are completely in contact, so that the wafer bonding interface of the wafer pair 200 on the load-bearing side 21 is subjected to uniform pressing force, effectively avoiding uneven force distribution.

[0042] In one embodiment, the support includes a support ring 1 and a carrier plate 2 disposed within the support ring 1, with the carrier plate 2 serving as the bearing portion. The support ring 1 provides stable support for the positioning assembly 3 and the carrier plate 2, ensuring the rigidity of the wafer bonding fixture. The carrier plate 2 supports the wafer pair 200 and directly bears the bonding pressure. By configuring the carrier plate 2 and the support ring 1 as separate structures, the carrier plate 2 can be independently selected from a specific material highly compatible with the wafer bonding process, significantly different from the material of the support ring 1, thereby avoiding the adverse effects of the material properties of the support ring 1 on the bonding interface quality and uniformity.

[0043] In one embodiment, the support plate 2 is a silicon carbide plate. The high hardness, high thermal conductivity, and semiconductor process compatibility of silicon carbide can more effectively transfer pressure, manage thermal stress, and ensure the purity and consistency of the wafer bonding process.

[0044] In one embodiment, the carrier plate 2 is fixed within the support ring 1 by fixing components distributed circumferentially thereafter. The fixing components distributed circumferentially ensure precise alignment and fixation of the carrier plate 2 within the support ring 1. First, this ensures the accuracy and stability of the center position of the carrier plate 2 relative to the support ring 1, directly guaranteeing the uniformity and accuracy of the wafers subsequently placed on the carrier plate 2 with respect to the 200 positioning reference. Second, the uniformly distributed fixing force effectively prevents the carrier plate 2 from skewing, warping, or rotating when subjected to bonding pressure or process temperature changes, maintaining the flatness and levelness of the carrier portion. This avoids wafer displacement or additional stress caused by localized stress concentration or deformation, thereby providing a stable, reliable, and geometrically consistent carrier side 21 for wafer bonding.

[0045] For example, three fixing components are provided, and the three fixing components are evenly distributed along the circumference of the support plate 2. Of course, in other embodiments, the number of fixing components can be designed according to the diameter of the support plate 2. For a support plate 2 with a larger diameter, more fixing components are provided; for a support plate 2 with a smaller diameter, fewer fixing components are provided.

[0046] In one embodiment, the fixing component includes a limiting pin 41. The support ring 1 has a limiting hole that extends radially through it, and the bearing plate 2 has a limiting groove 22 circumferentially. The limiting pin 41 passes through the limiting hole and is inserted into the limiting groove 22. The limiting pin 41 passes through the limiting hole from the outer wall of the support ring 1 and is inserted into the limiting groove 22, locking the center position of the bearing plate 2 relative to the support ring 1 in the radial direction, ensuring the precise coaxiality of the bearing plate 2 and the support ring 1; at the same time, it constrains the bearing plate 2 to prevent rotation and overturning, ensuring the positional accuracy of the bearing plate 2. In addition, the inner wall of the support ring 1 and the outer wall of the bearing plate 2 can be clearance-fitted, allowing the bearing plate 2 to expand along its planar direction when heated, significantly alleviating the problem of thermal stress concentration caused by the difference in the thermal expansion coefficients of the support ring 1 and the bearing plate 2. Finally, this connection method is simple, reliable, easy to process and assemble, and the insertion connection of the limiting pin 41 facilitates the quick installation, disassembly, and replacement of the bearing plate 2, improving assembly efficiency.

[0047] In one embodiment, the fixing assembly further includes a fastening screw 42, and the support ring 1 is also provided with a threaded hole 11 communicating with the limiting hole. The fastening screw 42 is screwed into the threaded hole 11 and abuts against the limiting pin 41 to lock the limiting pin 41. After the limiting pin 41 is inserted and positioned, the axial pressure generated by tightening the fastening screw 42 acts directly on the limiting pin 41, eliminating the risk of radial or axial loosening that may occur during tooling vibration, handling, or repeated assembly of wafer pairs 200, and ensuring the connection rigidity and long-term positional stability between the carrier plate 2 and the support ring 1.

[0048] For example, there are two fastening screws 42 and two threaded holes 11, which are arranged in a one-to-one correspondence. The two threaded holes 11 are arranged radially spaced along the support ring 1 to ensure the stability of the connection.

[0049] In one embodiment, the limiting hole includes a connected large-diameter hole and a small-diameter hole, and the limiting pin 41 includes a connected large-diameter pin and a small-diameter pin. The large-diameter pin is located inside the large-diameter hole, and the small-diameter pin is inserted into the limiting groove 22. The fastening screw 42 abuts against the stepped surfaces of the large-diameter pin and the small-diameter pin. This composite structure design of stepped hole-stepped pin-screw top stepped surface significantly improves the positioning accuracy, anti-displacement capability, and thermal stress adaptability of the fixing component. The cooperation between the large-diameter hole and the large-diameter pin provides ample initial assembly clearance and guiding effect, greatly reducing the difficulty of aligning and installing the bearing plate 2 and the support ring 1. When the small-diameter pin is precisely inserted into the limiting groove 22 of the bearing plate 2, its tight fit with the small-diameter hole establishes a high-precision radial positioning reference. The fastening screw 42 directly presses against the stepped surface of the large-diameter pin and the small-diameter pin, generating a highly concentrated axial locking force. This force acts perpendicularly to the pin axis, which not only strongly suppresses any possible axial movement of the limiting pin 41, but more importantly, through the rigid transmission of the stepped surface, the locking torque is efficiently converted into a stable support for the tail of the small-diameter pin (i.e., the precision positioning section), which greatly enhances the small-diameter pin's ability to resist radial shear loads (such as uneven bonding pressure or vibration), effectively preventing it from undergoing micro-displacement or deformation in the small-diameter hole, thereby ensuring the long-term rigidity and repeatability of the core positioning interface.

[0050] For example, such as Figure 5 As shown, of the two fastening screws 42, one fastening screw 42 abuts against the stepped surfaces of the large-diameter pin and the small-diameter pin, and the other fastening screw 42 abuts against the end of the small-diameter pin away from the large-diameter pin. The length of the large-diameter hole is greater than the length of the large-diameter pin, so that one of the fastening screws 42 can abut against the stepped surface.

[0051] In one embodiment, such as Figure 6 As shown, the positioning component 3 includes a positioning disk 31 and positioning pins 32. The positioning disk 31 is located axially on the support portion, and the positioning pins 32 are retractable and extendable on the positioning disk 31, allowing the wafer pair 200 to be placed within the support side 21 and abut against the positioning pins 32, thereby achieving positioning of the wafer pair 200. The positioning disk 31 is fixed to the support ring 1 to provide a stable reference platform, ensuring that the extension and retraction trajectories of all positioning pins 32 are precisely controllable. The retracted state of the positioning pins 32 provides unobstructed operating space for the placement of the wafer pair 200, allowing the wafers to be placed smoothly on the support side 21, avoiding the risks of wafer loading interference, scratches, or edge chipping caused by fixed positioning pins. The active reset of the positioning pins 32 can precisely abut against the edge of the wafer pair 200, applying a uniform constraint force in the radial direction, so that the wafer pair 200 can be centered on the support side 21, while providing reliable circumferential anti-slip clamping.

[0052] For example, the positioning pin 32 is retractably mounted on the positioning disk 31 by means of a spring. There are three positioning components 3, two of which are each provided with one positioning pin 32, and the other positioning component 3 is provided with two positioning pins 32. The two positioning pins 32 are used to position the cut surface 201 of the wafer.

[0053] In one embodiment, the wafer bonding fixture further includes spacer pressing components 5, which are evenly distributed around the circumference of the support portion and alternate with positioning components 3. Three spacer pressing components 5, three positioning components 3, and three fixing components are each provided, and these components are alternately arranged. This design, with three spacer pressing components 5, three positioning components 3, and three fixing components evenly distributed alternately at 120° around the circumference of the support portion, allows the positioning components 3 to focus on radial centering, the spacer pressing components 5 to independently provide vertically downward flexible pressure, and the fixing components to ensure the mechanical stability of the support plate 2. The alternating spatial arrangement of these three components maximizes the use of the limited annular space and prevents movement conflicts. Furthermore, the symmetrical layout of the three-point pressing transmits highly uniform distributed pressure to the wafer edge during bonding, effectively compensating for the pressure attenuation of the central pressure head at the wafer edge, significantly improving the uniformity of pressure distribution at the bonding interface, directly suppressing micro-gap or bubble defects caused by insufficient edge pressure, and further ensuring the quality of wafer bonding.

[0054] The spacer pressing assembly 5 includes a spacer pad and a pressing element. The spacer pad is used to isolate the two wafers in an atmospheric environment, preventing the atmosphere from being trapped during bonding and affecting the quality of the bonded wafers. The pressing element can press the two wafers together after alignment, preventing them from shifting and ensuring stable transfer of the aligned wafers between different process stages, thus ensuring alignment accuracy.

[0055] The specific structure of the interval pressing component 5 can be referred to the existing technology design. This is not the focus of the improvement in this embodiment, and will not be described in detail here.

[0056] This embodiment also provides a bonding apparatus, including the wafer bonding fixture described above, which can ensure the pre-alignment of the wafer pair 200 before bonding; and ensure that the entire bonding surface of the wafer pair 200 is subjected to uniform force during bonding, and that the bonding interface is tightly bonded, thereby ensuring bonding quality and improving product yield.

[0057] The above description is only a preferred embodiment of this utility model. For those skilled in the art, there will be changes in the specific implementation method and application scope based on the idea of ​​this utility model. The content of this specification should not be construed as a limitation of this utility model.

Claims

1. A wafer bonding tool, characterized by, include: The support member has a bearing portion having a bearing side (21) and a non-bearing side (23). The bearing side (21) is used to bear a wafer pair (200), and the projection of the wafer pair (200) is completely located within the bearing side (21). The non-bearing side (23) is used to receive external forces. The positioning component (3) is arranged circumferentially on the support portion to position the wafer pair (200) on the support side (21).

2. The wafer bonding tool of claim 1, wherein, The support member includes a support ring (1) and a bearing plate (2) disposed within the support ring (1), wherein the bearing portion is the bearing plate (2).

3. The wafer bonding tool of claim 2, wherein, The support plate (2) is a silicon carbide plate.

4. The wafer bonding fixture according to claim 2, characterized in that, The bearing plate (2) is fixed to the support ring (1) by fixing components distributed along its circumference.

5. The wafer bonding tool of claim 4, wherein, The fixing component includes a limiting pin (41), the support ring (1) is provided with a limiting hole that is radially through, and the bearing plate (2) is provided with a limiting groove (22) in the circumferential direction. The limiting pin (41) passes through the limiting hole and is inserted into the limiting groove (22).

6. The wafer bonding tool of claim 5, wherein, The fixing assembly also includes a fastening screw (42), and the support ring (1) is also provided with a threaded hole (11) communicating with the limiting hole. The fastening screw (42) is screwed into the threaded hole (11) and abuts against the limiting pin (41) to lock the limiting pin (41).

7. The wafer bonding tool of claim 6, wherein, The limiting hole includes a large diameter hole and a small diameter hole connected together, and the limiting pin (41) includes a large diameter pin and a small diameter pin connected together. The large diameter pin is located in the large diameter hole, and the small diameter pin is inserted into the limiting groove (22). The fastening screw (42) abuts against the stepped surfaces of the large-diameter pin and the small-diameter pin.

8. The wafer bonding tool of claim 1, wherein, The positioning component (3) includes a positioning disk (31) and a positioning pin (32). The positioning disk (31) is located in the circumference of the bearing portion, and the positioning pin (32) is retractably located in the positioning disk (31) so that the wafer pair (200) can be placed in the bearing side (21) and abut against the positioning pin (32).

9. The wafer bonding tool of any of claims 1-8, wherein, The wafer bonding fixture further includes a spacer pressing component (5), which is arranged circumferentially on the support portion and alternately arranged with the positioning component (3).

10. The wafer bonding tool of any of claims 1-8, wherein, The non-load-bearing side (23) is used to contact the press, and the area of ​​the non-load-bearing side (23) is the same as the area of ​​the pressing surface of the press.

11. Bonding apparatus characterized in that Includes the wafer bonding fixture as described in any one of claims 1-10.

Images