Wafer bonding pair clamping reinforcement jig for ion implantation lift-off process

Abstract

This invention discloses a wafer bonding pair clamping and reinforcement fixture for ion implantation lift-off processes, including a base and a clamping unit for applying axial pressure to the wafer bonding pair, and a centering unit disposed on the base. The centering unit includes at least three radially moving stops evenly spaced around the central axis of the base. The radially moving stops are slidably connected to the base and used to abut against the edges of the wafer bonding pair to be clamped. Support seats are spaced below the base, and a central guide rod coaxial with the base is disposed between the base and the support seats. The two ends of the central guide rod are fixed to the base and the support seats respectively. A transmission sleeve is sleeved on the central guide rod, and a synchronous connector is disposed between the transmission sleeve and each radially moving stop. The synchronous connector passes through the base and its two ends are hinged to the transmission sleeve and the corresponding radially moving stop respectively. The centering or release operation of the wafer bonding pair to be clamped is realized by moving the transmission sleeve.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing equipment technology, and more specifically to a wafer bonding pair clamping and reinforcement fixture used in ion implantation and stripping processes. Background Technology

[0002] With societal development and continuous advancements in wireless communication technology, 5G has become a focal point, presenting both new opportunities and challenges for radio frequency (RF) filters, a core component in 5G communication. In semiconductor manufacturing, ion implantation and lift-off techniques are commonly used to transfer piezoelectric single-crystal thin films from source wafers to a substrate. This process involves bonding the target wafer to the substrate to form a "bond pair," followed by annealing at a specific temperature to utilize thermal stress and separate the film along the implantation interface. To improve production efficiency, multiple wafer bond pairs are typically stacked and then placed in a fixture for heat treatment. Before clamping, ensuring the central axes of each wafer are aligned (i.e., centering) is crucial. If there is eccentricity between wafers, the axial pressure distribution will be uneven, leading to thermal stress imbalance during annealing and potentially causing film cracking or edge defects. Currently, operators typically rely on visual inspection and manual adjustment of wafer positions. However, when multiple wafers are stacked, the lower wafer is obscured, limiting observation and making it difficult to guarantee centering accuracy, severely impacting yield. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a clamping and reinforcing fixture that can quickly achieve accurate alignment of multi-wafer bonding pairs and improve alignment efficiency.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A wafer bonding pair clamping and reinforcement fixture for ion implantation lift-off processes includes a base for supporting the wafer bonding pairs and a clamping unit for applying axial pressure to the wafer bonding pairs. It also includes an alignment unit disposed on the base. The alignment unit includes at least three radially movable stops evenly spaced around the central axis of the base. These radially movable stops are slidably connected to the base and capable of moving radially along the base to abut against the edges of the wafer bonding pairs to be clamped. Each radially movable stop is equidistant from the center of the base. Support seats are spaced apart below the base, and a clamping device (equivalent to the base) is disposed between the base and the support seats. The shaft has a central guide rod, with its two ends fixed to the base and support respectively to provide support for the base. A transmission sleeve is fitted on the central guide rod, which can slide along the length of the central guide rod. A synchronous connector is provided between the transmission sleeve and each radial moving stop. The synchronous connector passes through the base and its two ends are hinged to the transmission sleeve and the corresponding radial moving stop respectively. When the transmission sleeve moves along the length of the central guide rod, the transmission sleeve can drive each radial moving stop to move synchronously radially through the synchronous connector, so as to realize the centering or release operation of the wafer bonding pair to be clamped.

[0006] In this invention, the transmission sleeve moves axially along the central guide rod, and the synchronous connecting member drives all the radial moving stops to move synchronously radially. They abut against the edges of the stacked wafer bonding pairs from multiple directions and push them toward the center, thereby achieving rapid and accurate alignment of the wafer bonding pairs. This avoids subjective errors caused by manual operation and significantly improves alignment efficiency and consistency.

[0007] As an optimization, the clamping unit includes a top cover disposed above and spaced apart from the base. An adjusting screw threadedly through the top cover along the axial direction of the base is threaded onto the top cover. A pressure plate is fixedly connected to one end of the adjusting screw facing the base. The side of the pressure plate facing the base is a pressing surface parallel to the upper surface of the base. Upper connecting rods, fixedly connected to the top cover and the base, are also provided to provide support for the top cover. This converts rotational motion into axial linear motion of the pressure plate, achieving stable and controllable axial pressure on the wafer bonding pair.

[0008] As an optimization, an operating sleeve is also fitted onto the central guide rod on the side of the transmission sleeve away from the base. The operating sleeve can slide along the length of the central guide rod. An elastic element is provided between the transmission sleeve and the operating sleeve, with both ends of the elastic element fixedly connected to the transmission sleeve and the operating sleeve, respectively. A positioning and locking device is provided on the operating sleeve, which can position and lock the operating sleeve on the central guide rod. By sliding the operating sleeve, the transmission sleeve is moved via the elastic element, thereby driving the stop to center. After the stop contacts the wafer edge, the elastic element is further stretched when the operating sleeve is pulled down. The resistance force of the stop on the wafer is determined by the stretching amount of the elastic element, achieving flexible centering with controllable resistance force and avoiding rigid compression damage to the wafer edge. After centering is completed, the operating sleeve is locked to facilitate subsequent pressure fixing operations.

[0009] As an optimization, the elastic element is a cylindrical helical spring sleeved on the central guide rod. The cylindrical helical spring has a simple structure, low cost, and allows for direct observation of the stretching amount to adjust the centering resistance force.

[0010] As an optimization, the positioning and locking device includes a positioning bolt. A positioning screw hole is provided on the sleeve body along the radial direction of the sleeve, communicating with the inner hole of the sleeve. The threaded section of the positioning bolt is threaded into the positioning screw hole, and the sleeve is locked and positioned by pressing against the central guide rod. By tightening the positioning bolt so that its end presses against the central guide rod, the sleeve can be positioned and fixed. The structure is simple and the operation is convenient.

[0011] As an optimization, a guide groove extending radially along the base is provided on the base corresponding to the position of each radially moving stop. The guide groove is a dovetail groove or a T-shaped groove, and it extends through the thickness direction of the base. The radially moving stop is slidably embedded in the guide groove, and the synchronous connector passes through the guide groove and is hinged to the bottom of the corresponding radially moving stop. The dovetail groove or T-shaped groove can prevent the radially moving stop from falling off the base during sliding, and also facilitates the synchronous connector to pass through the guide groove and be hinged to the bottom of the radially moving stop.

[0012] As an optimization, the radially moving stop includes a slide block slidably embedded in the guide groove. A stop post is fixedly connected to the top of the slide block. The stop post is cylindrical, and its axis is parallel to the axis of the base. The height of the upper end of the stop post is no higher than the top height of the stacked wafer bonding pairs to be clamped. The cylindrical stop post makes line contact with the edge of the wafer, resulting in a small contact area and minimizing damage to the wafer. Furthermore, the height of the stop post ensures that the lower surface of the pressure plate will not interfere with the stop post during subsequent pressurization.

[0013] As an optimization, a connecting stud extends coaxially from the lower end of the stop post, and a connecting screw hole is provided on the top of the slide block to mate with the connecting stud. The stop post is detachably connected to the slide block through the engagement of the connecting stud and the connecting screw hole. For different numbers of wafer bonding pairs (i.e., different stacking heights), stop posts with different axial heights can be quickly replaced, making operation simple and convenient.

[0014] As an optimization, a lower connecting rod is also provided between the base and the support base, and fixedly connected to them respectively, to provide auxiliary support for the base. The lower connecting rod and the central guide rod jointly support the base, enhancing the rigidity and stability of the overall structure.

[0015] Compared with the prior art, the present invention, by setting an alignment unit on the base consisting of radially moving stops, transmission sleeves and synchronous connectors, can adjust the stacked wafer bonding pairs to be coaxial with the base, avoiding the error of manual visual alignment and significantly improving alignment accuracy and operating efficiency. Attached Figure Description

[0016] Figure 1 This is a side view of the present invention;

[0017] Figure 2 This is a top view of the base in this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention 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 the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not indicate that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] like Figure 1 and Figure 2As shown in the figure, the wafer bonding pair clamping and reinforcement fixture for the ion implantation lift-off process in this specific embodiment includes a base 1 for supporting the wafer bonding pair and a clamping unit for applying axial pressure to the wafer bonding pair. It also includes an alignment unit disposed on the base. The alignment unit includes three radially moving stops evenly spaced around the central axis of the base 1. The radially moving stops are slidably connected to the base 1 and can move radially along the base 1 to abut against the edges of the wafer bonding pair to be clamped. Each radially moving stop is equidistant from the center of the base 1. Support seats 2 are spaced apart below the base 1, and a clamping device with the same diameter as the base 1 is disposed between the base 1 and the support seats 2. The central guide rod 3 of the shaft is fixed at both ends to the base 1 and the support 2 respectively to provide support for the base 1. A transmission sleeve 4 is sleeved on the central guide rod 3. The transmission sleeve 4 can slide along the length of the central guide rod 3. A synchronous connector 5 is provided between the transmission sleeve 4 and each radial moving stop. The synchronous connector 5 passes through the base 1 and its two ends are hinged to the transmission sleeve 4 and the corresponding radial moving stop respectively. When the transmission sleeve 4 moves along the length of the central guide rod 3, the transmission sleeve 4 can drive each radial moving stop to move synchronously radially through the synchronous connector 5 to realize the centering or release operation of the wafer bonding pair to be clamped.

[0021] The clamping unit includes a top cover 6 disposed above and spaced apart from the base 1. An adjusting screw 7 threadedly engages with the top cover 6 along the axial direction of the base 1. A pressure plate 8 is fixedly connected to one end of the adjusting screw 7 facing the base 1. The side of the pressure plate 8 facing the base 1 is a pressing surface parallel to the upper surface of the base 1. An upper connecting support rod 9 is also provided between the top cover 6 and the base 1 and fixedly connected thereto, for providing support for the top cover 6.

[0022] An operating sleeve 10 is also fitted on the central guide rod 3 on the side of the transmission sleeve 4 away from the base 1. The operating sleeve 10 can slide along the length of the central guide rod 3. An elastic element 11 is provided between the transmission sleeve 4 and the operating sleeve 10. The two ends of the elastic element 11 are fixedly connected to the transmission sleeve 4 and the operating sleeve 10, respectively. A positioning and locking device is provided on the operating sleeve 10, which can position and lock the operating sleeve 10 on the central guide rod 3.

[0023] The elastic element 11 is a cylindrical helical spring sleeved on the central guide rod 3.

[0024] The positioning and locking device includes a positioning bolt 12. The operating sleeve 10 has a positioning screw hole along the radial direction of the operating sleeve 10. The positioning screw hole communicates with the inner hole of the operating sleeve 10. The screw section of the positioning bolt 12 is threaded in the positioning screw hole. The operating sleeve 10 is locked and positioned by pressing against the central guide rod 3.

[0025] The base 1 is provided with a guide groove 13 extending radially along the base 1 at the position of each of the radially moving stops. The guide groove 13 is a dovetail groove and passes through the thickness direction of the base 1. The radially moving stops are slidably embedded in the guide groove 13. The synchronous connector 5 passes through the guide groove 13 and is hinged to the bottom of the corresponding radially moving stop.

[0026] The radial moving stop includes a slide block 14 slidably embedded in the guide groove 13. A stop post 15 is fixedly connected to the top of the slide block 14. The stop post 15 is cylindrical and its axis is parallel to the axis of the base 1. The height of the upper end of the stop post 14 is not higher than the top height of the wafer bonding pairs to be clamped after stacking.

[0027] The lower end of the stop post 15 is coaxially extended with a connecting stud, and the top of the slide block 14 is provided with a connecting screw hole that mates with the connecting stud. The stop post 15 is detachably connected to the slide block 14 through the engagement of the connecting stud and the connecting screw hole.

[0028] A lower connecting rod 16 is also provided between the base 1 and the support base 2 and is fixedly connected thereto, for providing auxiliary support for the base 1.

[0029] Considering that the fixture needs to be used in a high-temperature annealing environment, the main components such as the base, support, guide rod, transmission sleeve, slide, stop, and elastic element (spring) should be made of high-temperature resistant materials. High-temperature solid lubricant can be used between the guide groove and the slide to reduce friction.

[0030] In addition, the stop post and the slide are connected by a threaded detachable connection. For different numbers of wafer bonding pairs (i.e. different total stacking heights), stop posts with different axial heights can be selected for replacement to ensure that the upper end of the stop post is never higher than the top of the wafer bonding pair. This allows the fixture to flexibly adapt to different process requirements.

[0031] In addition, the adjusting screw and the pressure plate can be connected by a bearing. This way, when the pressure plate contacts the wafer surface, the pressure plate will remain stationary due to friction, thus preventing wear between the pressure plate and the wafer.

[0032] The usage method of this embodiment is as follows:

[0033] Initial state: The operating sleeve is at the top of its stroke (close to the transmission sleeve), the transmission sleeve is at the top of its stroke (close to the base), and the elastic element is in its natural state. At this time, the three radial moving stops are driven to the outermost position through the synchronous connecting parts (connecting rods), and the diameter of the inscribed circle formed by each stop post is greater than the outer diameter of the wafer bonding pair.

[0034] Alignment operation: Roughly stack multiple wafer bonding pairs on the center area of ​​the upper surface of the base. Pull the operating sleeve downward by hand to move it downward. At the same time, the elastic element is stretched and applies a downward pulling force to the transmission sleeve. Under the action of the pulling force, the transmission sleeve slides down along the central guide rod. Through the synchronous connector, it pushes the three slide blocks and the stop post to move radially inward in sync. When the stop post contacts the edge of the wafer bonding pair, the off-center wafer bonding pair will be pushed by the stop post to a position coaxial with the base, thus completing the alignment.

[0035] After alignment, the downward movement of the transmission sleeve is stopped due to resistance. The operating sleeve is pulled down further, and the elastic element is stretched further. The tension of the elastic element on the transmission sleeve gradually increases. This tension is converted into a radial abutment force of the stop post against the wafer edge through the synchronous connector. By controlling the stretch of the elastic element, the abutment force is controlled within a preset range to ensure that the wafer alignment is secure without damaging the wafer edge. Tighten the positioning bolt to lock the operating sleeve on the center guide rod.

[0036] Axial pressure: Tighten the adjusting screw to drive the pressure plate to descend. The lower surface of the pressure plate contacts the upper surface of the uppermost wafer. Continue to tighten the adjusting screw to the set torque to apply stable axial pressure to the wafer bonding pair. After clamping, reverse the positioning bolt and push the operating sleeve upward. Through the synchronous connector, push the three slides and the stop to move radially outward in sync, so that the stop separates from the edge of the wafer.

[0037] Annealing and disassembly: The clamped fixture is placed into the annealing furnace for heat treatment to complete the film peeling. After annealing, the fixture is removed, the adjusting screw is loosened to raise the pressure plate, and the peeled wafer is removed.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described with reference to preferred embodiments, those skilled in the art should understand that various changes in form and detail can be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A wafer bonding pair clamping and reinforcement fixture for use in an ion implantation lift-off process, comprising a base for supporting the wafer bonding pair and a clamping unit for applying axial pressure to the wafer bonding pair, characterized in that: It also includes a centering unit mounted on a base; the centering unit includes at least three radially moving stops evenly spaced around the central axis of the base. The radially moving stops are slidably connected to the base and can move radially along the base to abut the edges of the wafer bonding pairs to be clamped. Each radially moving stop is equidistant from the center of the base. Support seats are spaced below the base, and a central guide rod coaxial with the base is provided between the base and the support seats. The two ends of the central guide rod are fixed to the base and the support seats respectively to provide support for the base. A transmission sleeve is fitted on the central guide rod, and the transmission sleeve can slide along the length of the central guide rod. A synchronous connector is provided between the transmission sleeve and each radially moving stop. The synchronous connector passes through the base and its two ends are hinged to the transmission sleeve and the corresponding radially moving stop respectively. When the transmission sleeve moves along the length of the central guide rod, the transmission sleeve can drive each radially moving stop to move synchronously radially through the synchronous connector to realize the centering or release operation of the wafer bonding pairs to be clamped.

2. The wafer bonding pair clamping and reinforcement fixture for ion implantation lift-off process according to claim 1, characterized in that: The clamping unit includes a top cover disposed above and spaced apart from the base. An adjusting screw threadedly through the top cover along the axial direction of the base is threaded onto the top cover. A pressure plate is fixedly connected to one end of the adjusting screw facing the base. The side of the pressure plate facing the base is a pressing surface parallel to the upper surface of the base. An upper connecting support rod is also provided between the top cover and the base and fixedly connected thereto to provide support for the top cover.

3. The wafer bonding pair clamping and reinforcement fixture for ion implantation lift-off process according to claim 1, characterized in that: An operating sleeve is also fitted on the central guide rod located on the side of the transmission sleeve away from the base. The operating sleeve can slide along the length of the central guide rod. An elastic element is provided between the transmission sleeve and the operating sleeve. The two ends of the elastic element are fixedly connected to the transmission sleeve and the operating sleeve, respectively. A positioning and locking device is provided on the operating sleeve, which can position and lock the operating sleeve on the central guide rod.

4. The wafer bonding pair clamping and reinforcement fixture for ion implantation lift-off process according to claim 3, characterized in that: The elastic element is a cylindrical helical spring sleeved on the central guide rod.

5. The wafer bonding pair clamping and reinforcement fixture for ion implantation lift-off process according to claim 3, characterized in that: The positioning and locking device includes a positioning bolt. The operating sleeve has a positioning screw hole along the radial direction of the operating sleeve. The positioning screw hole communicates with the inner hole of the operating sleeve. The screw section of the positioning bolt is threaded in the positioning screw hole. The operating sleeve is locked and positioned by pressing against the central guide rod.

6. The wafer bonding pair clamping and reinforcement fixture for ion implantation lift-off process according to claim 1, characterized in that: The base is provided with guide grooves extending radially along the base for each radially moving stop. The guide grooves are dovetail grooves or T-shaped grooves and extend through the thickness direction of the base. The radially moving stop is slidably embedded in the guide groove. The synchronous connector passes through the guide groove and is hinged to the bottom of the corresponding radially moving stop.

7. The wafer bonding pair clamping and reinforcement fixture for ion implantation lift-off process according to claim 6, characterized in that: The radial moving stop includes a slide block slidably embedded in the guide groove. A stop post is fixedly connected to the top of the slide block. The stop post is cylindrical and its axis is parallel to the axis of the base. The height of the upper end of the stop post is not higher than the top height of the stacked wafer bonding pairs to be clamped.

8. The wafer bonding pair clamping and reinforcement fixture for ion implantation lift-off process according to claim 7, characterized in that: The lower end of the stop post is coaxially extended with a connecting stud, and the top of the slide block is provided with a connecting screw hole that mates with the connecting stud. The stop post is detachably connected to the slide block through the engagement of the connecting stud and the connecting screw hole.

9. The wafer bonding pair clamping and reinforcement fixture for ion implantation lift-off process according to claim 1, characterized in that: A lower connecting rod is also provided between the base and the support base and is fixedly connected to them respectively, for providing auxiliary support for the base.

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