Chip bonding device for improving bonding quality of chip and lead frame

Abstract

The invention relates to a chip bonding device for improving the bonding quality of a chip and a lead frame. The chip bonding device comprises a base, a rotating frame and a limiting mechanism, a rotating frame is installed on the base and rotates around the center of the base, a limiting mechanism is arranged on the rotating frame and comprises a fixing base and a pair of clamping claws arranged on the upper side of the fixing base, the fixing base is fixedly arranged on the rotating frame and rotates along with rotation of the rotating frame, and an installation groove is formed in the inner surface of the fixing base. The lead frame is adaptively placed in the mounting groove, the chip is clamped by the clamping claws arranged above the fixed seat, the clamping claws are arranged on the left and right sides and can be driven by the power sources to move relatively, and the buffer parts are arranged in the end parts of the clamping claws. In the buffer part, the chip is prevented from being damaged by overlarge clamping force or the chip is partially separated from the bonding layer on the lead frame through the spring piece. The beneficial effects of the invention are that layering between the wafer chip and the bonding layer and inclination of the chip can be avoided, and the working efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of wafer chip packaging technology, and in particular to a die bonding device for improving the bonding quality between the chip and the lead frame. Background Technology

[0002] Packaging is crucial for chips. Firstly, it isolates the chip from the outside world to prevent impurities in the air from corroding the chip circuitry and degrading its electrical performance. Secondly, packaged chips are easier to install and transport. The quality of packaging technology directly affects the chip's performance and subsequent installation and operation, making it paramount. Currently, after the wafer is diced into individual chips by dicing the wafer onto a blue film, the chips need to be bonded to the lead frame. Solder or epoxy resin are commonly used as bonding materials to secure the wafer chips to the lead frame. This technology is mature, reliable, and relatively inexpensive, and is widely used in discrete devices, analog chips, power devices, and various integrated circuits.

[0003] The bonding quality between the chip and the leadframe is a crucial factor determining the final reliability and lifespan of the packaged product. An ideal bonding interface requires a uniform adhesive layer thickness, no voids, a strong bond with the chip and leadframe interface, and the chip itself to be horizontal and highly parallel to the leadframe. However, current die bonding processes encounter the following problems in actual manufacturing: First, there is the issue of chip adhesive layer warpage and delamination. Due to temperature or excessive clamping force during die bonding, the adhesive layer may separate from the leadframe or the back of the chip, resulting in partial or overall separation (i.e., delamination). Warpage and delamination can lead to reduced chip stability, chip damage or cracks, and affect subsequent bonding processes, resulting in poor quality of the final packaged chip. Second, during die bonding, insufficient stability and alignment of the die bonding device may cause slight vibrations during pick-up and placement, leading to chip tilting. This slight height difference on the chip surface can affect subsequent bonding operations, and may even cause short circuits or stress concentration at certain locations on the chip, resulting in cracking.

[0004] Therefore, based on customer feedback regarding the shortcomings of the existing structure, the inventors made further improvements to overcome the aforementioned problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a die bonding device that can effectively avoid delamination between the wafer chip and the bonding layer and chip tilting, and improve work efficiency for improving the bonding quality between the chip and the lead frame.

[0006] The objective of this invention is achieved through the following technical solution: a die bonding device for improving the bonding quality between a chip and a lead frame, comprising a base, a rotating frame, and a limiting mechanism; A rotating frame is mounted on the base and rotates around the center of the base. A limiting mechanism is provided on the rotating frame. The limiting mechanism includes a fixed seat and a pair of clamping claws on the upper side of the fixed seat. The fixed seat is fixedly mounted on the rotating frame and rotates with the rotating frame. An installation groove is opened on the inner surface of the fixed seat. The installation groove is used to fit and place the lead frame. The chip is clamped by the clamping claws located above the fixed seat. Since the clamping claws are arranged on the left and right and are driven by a power source, they can move relative to each other. At the same time, a buffer part is provided at the end of the clamping claw. The buffer part is provided with a spring to avoid excessive clamping force from damaging the chip or causing the chip to partially separate from the adhesive layer on the lead frame.

[0007] As a preferred technical solution of this application, the rotating frame is a cross-shaped plate with a limiting mechanism at each of the four ends. The upper surface of the four ends is connected to a circular mounting plate, and the upper surface of the circular mounting plate is fixedly connected to the limiting mechanism. Four sets of plates are glued at one time, thereby improving work efficiency.

[0008] As a preferred technical solution of this application, a lifting mechanism is also included, which includes an electric rod and a fixed claw; The electric rod is located at the center of the base and is driven by motor B. A fixed claw is connected to the upper end of the electric rod. The fixed claw includes a connecting plate and a claw end. One end of the connecting plate is connected to the electric rod, and the other end is connected to the claw end. The claw end is a concave claw. Motor B drives the electric rod to move downward until the claw end clamps the chip that has been rotated to that position and moves the chip down to contact the adhesive layer on the lead frame.

[0009] As a preferred technical solution of this application, a rotating motor is connected below the rotating frame. The rotating frame is driven by the rotating motor to rotate, thereby causing each limiting mechanism to move regularly and cyclically to the bottom of the claw of the fixed claw.

[0010] As a preferred technical solution of this application, the fixed seat of the limiting mechanism is a concave plate structure, which includes a bottom plate and left and right side plates. Motor A is installed on the left and right side plates. The motor shaft of motor A extends outward and is connected to the buffer part. The buffer part is connected to the clamping claw through a spring member.

[0011] As a preferred technical solution of this application, the buffer part includes a spring, a mounting cylinder, and a connecting cylinder; the bottom surface of the mounting cylinder is connected to the end of the motor shaft, and a spring is provided inside it. The bottom end of the spring is connected to the bottom surface of the mounting cylinder, and the other end is connected to the bottom surface of the connecting cylinder. One end of the connecting cylinder is open for the spring to extend into, and the connecting cylinder can move axially inside the mounting cylinder.

[0012] As a preferred technical solution of this application, the diameter of the connecting cylinder is smaller than the inner diameter of the mounting cylinder, and the front end of the connecting cylinder is connected to the clamping claw, so that the clamping claw moves axially with the connecting cylinder.

[0013] As a preferred technical solution of this application, the clamping claw has a concave structure and can be adapted to clamp the chip. There is a stepped platform between the clamping claw and the front end of the connecting cylinder. A long rod is vertically connected to the stepped platform, and the bottom end of the long rod is connected to a limiting block. When the opposing clamping claws clamp the chip in the center, the two opposing limiting blocks on the lower side of the clamping claws abut against the lead frame.

[0014] As a preferred technical solution of this application, the end face of the limiting block that holds the lead frame is made of rubber or silicone or other materials to avoid scratches and deformation of the lead frame.

[0015] The present invention has the following advantages: (1) Existing die bonding devices may cause the chip to delaminate from the adhesive layer or the chip itself when bonding. Delamination can lead to cracks or damage to the chip. This solution uses a spring in the buffer section to effectively absorb excessive force during the clamping process, prevent the chip from being damaged by pressure or the adhesive layer from delaminating, and improve the bonding reliability. (2) The existing device is not neutral and stable enough, which causes slight shaking during the picking and placing process, resulting in chip tilting. The slight height difference on the chip surface affects the subsequent bonding operation. This solution uses a lifting mechanism and a rotating frame to ensure that the chip does not shake or tilt during the placement process, keeps the chip parallel to the lead frame, and reduces the height difference. (3) The limiting blocks that limit and protect the lead frame in this solution are made of soft materials such as rubber to avoid scratching the lead frame during operation and ensure product quality. Attached Figure Description

[0016] Figure 1 This is a structural schematic diagram from a first perspective of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention from a side view. Figure 3 This is a schematic diagram of the limiting mechanism of the present invention; Figure 4 This is a schematic diagram of the structure of a pair of gripping claws in this invention; Figure 5 This is a schematic diagram of a half-section view of a pair of clamping claws in this invention; In the diagram: 1-base, 2-rotating frame, 3-fixed seat, 4-mounting groove, 5-clamping claw, 6-spring component, 7-mounting cylinder, 8-connecting cylinder, 9-motor A, 10-electric rod, 11-connecting plate, 12-claw end, 13-limiting block, 14-long rod. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0018] It should be noted that the orientation or positional relationship indicated by terms such as "left" and "right" is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, or the orientation or positional relationship in which those skilled in the art would conventionally understand it. Such terms are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0019] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.

[0020] Therefore, based on the above issues, please refer to Figure 1 This invention proposes a die bonding device to improve the bonding quality between the chip and the lead frame in order to solve the problem.

[0021] See Figures 1-5 The present embodiment proposes a die bonding device for improving the bonding quality between the chip and the lead frame, including a base 1, a rotating frame 2 and a limiting mechanism; Among them, see Figure 1 The base 1 is a square metal platform that provides stable support for the device. The rotating frame 2 is installed at the center of the base 1 and can rotate around the center of the base 1. A limit mechanism is provided on the upper surface of the rotating frame 2 and is fixedly installed on the rotating frame 2. When the rotating frame 2 rotates, the limit mechanism rotates with the rotating frame 2. The rotating frame 2 can continuously process multiple chips, thereby improving production efficiency. Among them, see Figure 1 and Figures 3-4 The limiting mechanism includes a fixed base 3 and a pair of opposing clamping claws 5 disposed above the fixed base 3. An installation groove 4 is provided on the inner surface of the fixed base 3 for placing the lead frame. The clamping claws 5 on the upper side of the installation groove 4 clamp the chip. The clamping claws 5 are symmetrically installed on the left and right and each is driven by a power source to move horizontally relative to each other. At the same time, a buffer part is provided at the end of the clamping claw 5. The buffer part is provided with a spring 6 to prevent excessive clamping force from damaging the chip or causing the chip to partially separate from the adhesive layer on the lead frame.

[0022] During operation, the lead frame with adhesive layer is first placed into the mounting slot 4 of the fixing base 3. At the same time, the chip is fed to the clamping claws 5 by the external feeding system. The clamping claws 5 are driven by the power source to move relative to each other, so that the chip is firmly clamped. At this time, the spring 6 in the buffer part is compressed. If the clamping force is too large, the spring 6 will be further compressed to avoid chip damage or delamination.

[0023] Existing die bonding processes have some problems in practical applications. Because existing die bonding devices typically use mechanical clamping to place the chip, the clamping force is not precisely controlled and lacks buffering, which can cause chip damage or breakage of the adhesive layer. This can easily lead to warping and delamination (i.e., partial or complete separation of the adhesive layer from the chip or lead frame), affecting subsequent bonding processes. Therefore, this solution designs a die bonding device to improve the bonding quality between the chip and the lead frame. By adding a buffer and a rotatable working frame 2, the stability and alignment of the chip are improved. Simultaneously, the buffer prevents the chip from being damaged by excessive clamping force, reducing the risk of chip damage and avoiding delamination.

[0024] In this embodiment, see Figure 1 For the rotating frame 2, the rotating frame 2 is designed as a cross plate structure, with a limiting mechanism installed at each of its four ends. The upper surface of each end is fixedly connected to the limiting mechanism via a circular mounting plate. A rotating motor is connected to the lower center of the rotating frame 2, and the rotating frame 2 is driven to rotate by the rotating motor, so that each limiting mechanism moves cyclically to the designated working position (such as directly below the lifting mechanism). The cross-shaped rotating frame 2 and the limiting mechanisms installed on it that rotate with the rotating frame 2 can perform chip bonding work in an orderly and cyclical manner, improving the overall work efficiency.

[0025] Further, see Figures 1-4 In the limiting mechanism, the fixed seat 3 is a concave plate structure. The fixed seat 3 includes a base plate and left and right side plates arranged perpendicular to the base plate. The lower surface of the base plate is fixedly connected to the circular mounting plate by screws or other connection methods. A motor A9 is installed on each of the left and right side plates. The motor shaft end of the motor A9 is connected to the buffer part, which includes a mounting cylinder 7, a spring 6 disposed in the mounting cylinder 7, and a connecting cylinder 8. The mounting cylinder 7 is cylindrical and its bottom surface is fixedly connected to the motor shaft. The motor A9 drives the left and right opposite mounting cylinders 7 to move towards each other. The mounting cylinder 7 is provided with a spring 6. One end of the spring 6 is welded to the inner bottom surface of the mounting cylinder 7, and its other end is connected to the inner bottom surface of the connecting cylinder 8. The diameter of the connecting cylinder 8 is smaller than that of the mounting cylinder 7. One end of the connecting cylinder 8 is open, and the spring 6 extends into the connecting cylinder 8 through the port. When the spring 6 is compressed, the connecting cylinder 8 moves axially in the mounting cylinder 7. The front end of the connecting cylinder 8 is connected to the clamping claw 5 through a stepped platform, thereby driving the clamping claw 5 to move axially together.

[0026] When motor A9 drives the gripper 5 to move, spring 6 provides cushioning to ensure that the gripping force is flexible and controllable, thus avoiding damage to the chip.

[0027] Furthermore, see Figures 3-5 The clamping claw 5 is a concave metal claw mechanism with an anti-slip pad on its inner surface to enhance clamping stability. A stepped platform is provided at the connection between the clamping claw 5 and the connecting cylinder 8. A long rod 14 extends vertically downwards from the edge of the stepped platform, and the bottom end of the long rod 14 is connected to a limiting block 13. One end of the limiting block 13 is made of silicone material, and its contact surface is adapted to the edge of the lead frame. When the clamping claw 5 clamps the chip, the limiting block 13 abuts against the edge of the lead frame to prevent displacement of the lead frame. The surface of the limiting block 13 in contact with the lead frame is made of soft materials such as rubber or silicone to avoid scratches or deformation.

[0028] In this embodiment, see Figure 1 and Figure 2 It also includes a lifting mechanism, which comprises an electric rod 10 and a fixed claw. The electric rod 10 is vertically mounted at the center of the base 1 and is driven by a motor B. The upper end of the electric rod 10 is connected to the claw end 12 of the fixed claw via a connecting plate 11. The claw end 12 has a concave structure for clamping the chip. When the limiting mechanism rotates the chip to below the fixed claw, the motor B drives the electric rod 10 to move downward, causing the claw end 12 to clamp the chip and press it against the adhesive layer on the lead frame, thus completing the bonding.

[0029] Workflow: The lead frame is placed into the mounting slot 4 of the fixing base 3 for initial fixation. At this time, the chip is fed between the clamping claws 5 by the external feeding system. The motor A9 is started to drive the clamping claws 5 to move relative to each other and clamp the chip. The spring 6 in the buffer part is compressed during the clamping process. If the clamping force is too large, the spring 6 is further compressed. The connecting cylinder 8 moves axially towards the mounting cylinder 7 to avoid chip damage. The electric rod 10 is driven by the motor B to move downward. The claw end 12 of the fixing claw clamps the chip and continues to press down, so that the chip contacts the adhesive layer on the lead frame. The adhesive layer is epoxy resin, which is pre-coated on the lead frame. The fixing claw remains stable and does not vibrate during the pressing process. The rotating motor drives the rotating frame 2 to rotate, so that one of the limiting mechanisms moves below the fixing claw. The rotation angle of the rotating frame 2 is controlled by the encoder to ensure accurate positioning. After one bonding is completed, the electric rod 10 is reset, and the rotating frame 2 rotates to the next station to the working point, repeating the above process. At the same time, the station that has completed bonding can be unloaded for the next process.

[0030] It should be noted that the entire device is coordinated by a PLC control system to achieve automated operation. At the same time, by adjusting the stiffness of spring 6 and the parameters of each motor used in this solution, it can adapt to chips and lead frames of different sizes, thus enhancing the practicality of the device.

[0031] Existing devices, when bonding chips and lead frames, are prone to chip damage or partial or complete separation (delamination) from the adhesive layer due to poor clamping force control. Furthermore, existing devices lack centering and stability, leading to minor vibrations or placement errors during bonding, causing chip tilting and affecting subsequent bonding processes. In addition, current devices have relatively low production efficiency. This solution incorporates an elastic buffer at the end of the clamping claw 5, with an internal spring 6, effectively absorbing and buffering excessive force during clamping and placement, preventing chip damage caused by excessive clamping force and avoiding partial separation of the chip from the uncured adhesive layer. The solution addresses the issue of ensuring the integrity and firmness of the bonding interface. Furthermore, by designing a rotating frame 2 and a lifting mechanism, along with the coordination of the limiting block 13 and the clamping claw 5, collaborative positioning is achieved. The rotating frame 2 rotates the chip regularly to a fixed working point, where the lifting mechanism performs unified picking and pressing actions. Simultaneously, the limiting block 13 and the clamping claw 5 limit the lead frame and clamping claw 5, achieving effective and stable centering, thus preventing chip tilting. In addition, this solution uses a rotatable cross-shaped rotating frame 2 to cyclically process the bonding of four chips to the lead frame, enabling parallel and seamless operation of multiple processes from loading to unloading, thereby improving production efficiency.

[0032] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A die bonding device for improving the bonding quality between a chip and a lead frame, characterized in that: It comprises a base (1), a rotating frame (2) and a limiting mechanism; The base (1) is provided with a rotating frame (2) which rotates around the center of the base (1), and the rotating frame (2) is provided with a limiting mechanism, which comprises a fixed seat (3) and a pair of clamping claws (5) arranged on the upper side of the fixed seat (3). The fixed seat (3) is fixedly arranged on the rotating frame (2) and rotates with the rotating frame (2). An installation groove (4) is formed in the inner surface of the fixed seat (3), which is used for accommodating the lead frame. The chip is clamped by the clamping claws (5) arranged above the fixed seat (3). Since the clamping claws (5) are arranged on the left and right sides and are respectively driven by a power source to move relatively, a buffer part is arranged at the end of the clamping claw (5). The spring element (6) in the buffer part prevents the chip from being damaged by excessive clamping force or causes the chip to be partially separated from the adhesive layer on the lead frame.

2. The die bonding apparatus of claim 1, wherein: The rotating frame (2) is a cross-shaped plate, and each of the four end heads is provided with a limiting mechanism. The upper surfaces of the four end heads are respectively connected to a circular mounting plate, and the upper surface of the circular mounting plate is fixedly connected to the limiting mechanism.

3. The die bonding device for improving the bonding quality between a chip and a lead frame according to claim 1, characterized in that: It also comprises a lifting mechanism, which comprises an electric rod (10) and a fixed claw. The electric rod (10) is located at the center of the base (1) and is driven by a motor B. The upper end of the electric rod (10) is connected to a fixed claw. The fixed claw comprises a connecting plate (11) and a claw end (12). One end of the connecting plate (11) is connected to the electric rod (10), and the other end is connected to the claw end (12). The claw end (12) is a concave claw. The motor B drives the electric rod (10) to move downward to clamp the chip rotated to this position and drive the chip to move downward to contact the adhesive layer on the lead frame.

4. A die bonding device for improving the bonding quality between a chip and a lead frame according to claim 2, characterized in that: A rotating motor is connected below the rotating frame (2). The rotating frame (2) is driven by the rotating motor to rotate, thereby driving each limiting mechanism to move regularly and circularly below the claw end (12) of the fixed claw.

5. The die bonding apparatus of claim 4, wherein: the die bonding apparatus further comprises a die bonding head having a plurality of die bonding pins; and the plurality of die bonding pins are arranged in a pattern corresponding to the pattern of the plurality of die bonding pins of the die bonding head. The fixed seat (3) of the limiting mechanism is a concave plate structure, which comprises a bottom plate and left and right side plates. A motor A (9) is arranged on the left and right side plates. The motor shaft of the motor A (9) is connected to the buffer part. The buffer part is connected to the clamping claw (5) through the spring element (6).

6. The die bonding apparatus of claim 5, wherein: The buffer part comprises a spring element (6), an installation cylinder (7) and a connecting cylinder (8). The bottom surface of the installation cylinder (7) is connected to the motor shaft end. A spring element (6) is arranged in the installation cylinder (7). The bottom end of the spring element (6) is connected to the inner bottom surface of the installation cylinder (7), and the other end is connected to the inner bottom surface of the connecting cylinder (8). The connecting cylinder (8) is open at one end for the spring element (6) to extend into, and the connecting cylinder (8) can move axially in the installation cylinder (7).

7. The die bonding apparatus of claim 6, wherein: The diameter of the connecting cylinder (8) is smaller than the inner diameter of the installation cylinder (7). The front end of the connecting cylinder (8) is connected to the clamping claw (5), so that the clamping claw (5) moves axially with the connecting cylinder (8).

8. The die bonding apparatus of claim 7, wherein: The clamping claw (5) is concave and can clamp the chip. The clamping claw (5) and the front end of the connecting cylinder (8) have a stepped platform, which is connected to a long rod (14) vertically downward, and the bottom end of the long rod (14) is connected to a limiting block (13). When the opposite clamping claws (5) clamp the chip in the middle, the opposite limiting blocks (13) on the lower side of the clamping claw (5) are driven to abut against the lead frame.

9. A die bonding device for improving the bonding quality between a chip and a lead frame according to claim 1, characterized in that: The end face of the limiting block (13) clamping the lead frame is made of rubber material or silica gel material, so as to avoid scratching and deforming the lead frame.

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