Bonding head assembly, bonding machine and bonding method

Abstract

The present invention aims to provide a bonding head assembly, a bonding machine and a bonding method. The bonding head assembly comprises a frame, a capillary, a first actuating unit, a second actuating unit and a cutter, wherein the capillary is movably connected to the frame in a first direction; the first actuating unit is fixed to the frame and is in transmission connection with the capillary, and during actuation, the first actuating unit can drive the capillary to move in the first direction relative to the frame; the second actuating unit is fixed on the frame; and the cutter is connected to the frame by means of the second actuating unit, the second actuating unit is in transmission connection with the cutter, and during actuation, the second actuating unit can drive the cutter to move in the first direction relative to the frame. During bonding, when moving in the first direction, the bonding head assembly can approach or move away from a workpiece to be bonded. By means of the bonding head assembly, the bonding machine and the bonding method, the working efficiency and quality of the bonding machine can be improved.

Description

Welding head assembly, bonding machine and bonding method Technical Field

[0001] The present invention relates to the technical field of welding, and in particular to a welding head assembly, a bonding machine and a bonding method. Background Art

[0002] Wire bonding is a method of using thin metal wires to weld metal wires to substrates using heat, pressure, and ultrasound to achieve electrical connection between the chip and the substrate.

[0003] Figure 1 shows a schematic diagram of a bonding head assembly in a conventional bonding machine. The bonding head assembly comprises a frame 90, a wedge 91, and a cutter 92. Wedge 91 has a wire channel within it. After the metal wire for bonding is drawn through this channel, the working portion of the free end of wedge 91 applies heat, pressure, and ultrasonic vibrations to the wire, bonding it to the substrate and completing the bonding process. After bonding is complete, the wire is severed by cutter 91.

[0004] In the existing welding head assembly shown in Figure 1, the blade 91 is flexibly connected to the frame 90, enabling relative movement in the Z direction. The cutter 92 is rigidly connected to the frame 90 in the Z direction and moves with the frame 90. The existing wire cutting method is as follows: after the blade 91 completes bonding the metal wire, the actuator 93 drives the frame 90, which is connected to the cutter 92, to move synchronously in the Z direction. At this time, due to the flexible connection between the blade 91 and the frame 90, the cutter 92 and the blade 91 can generate relative movement in the Z direction (overpressure). This overpressure causes the blade 91 to retract in the Z direction into the frame 90, exposing the cutter at its free end to complete the severing of the wire. After severing is completed, the actuator 93 drives the frame 90 upward, simultaneously lifting the blades 91 and 92 until they are free from the wire. However, the inventors have discovered that existing welding head assemblies still suffer from low bonding efficiency and low severing accuracy.

[0005] Summary of the Invention

[0006] The object of the present invention is to provide a welding head assembly that can improve the working efficiency and quality of a bonding machine.

[0007] To achieve the above-mentioned purpose, a welding head assembly is used in a bonding machine, which includes:

[0008] frame;

[0009] a riving knife movably connected to the frame along a first direction;

[0010] a first actuating unit, fixed to the frame and transmission-connected to the riving knife, capable of driving the riving knife to move relative to the frame along the first direction when actuated;

[0011] a second actuating unit fixed to the frame; and

[0012] a cutter connected to the frame via the second actuating unit, wherein the second actuating unit is in transmission connection with the cutter and is capable of driving the cutter to move relative to the frame along the first direction when actuated;

[0013] During bonding, when the welding head assembly moves along the first direction, it can approach or move away from the workpiece to be bonded.

[0014] In one or more embodiments, the riving knife is elastically connected to the frame to allow the riving knife to move relative to the frame along the first direction.

[0015] In one or more embodiments, the riving knife is elastically connected to the frame via a spring sheet.

[0016] In one or more embodiments, a cutter spring sheet is provided between the cutter and the frame.

[0017] In one or more embodiments, a guide assembly is provided between the cutter and the frame, and the guide assembly enables the cutter to move in a direction with a component relative to the first direction when the second actuating unit is actuated.

[0018] In one or more embodiments, the riving knife is a wedge-shaped riving knife.

[0019] In one or more embodiments, the welding head assembly further includes a third actuating unit, which is in transmission connection with the frame and can drive the entire frame to move along the first direction when actuated.

[0020] In one or more embodiments, the first actuating unit and / or the second actuating unit and / or the third actuating unit is a linear motor.

[0021] In one or more embodiments, in an initial state, the riving knife and the cutting knife extend out to the same distance relative to the bottom surface of the frame.

[0022] On the other hand, according to some embodiments of the present application, a bonding machine is provided, which includes the bonding head assembly as described above.

[0023] On the other hand, according to some embodiments of the present application, a bonding method is provided, which uses the bonding machine as described above to bond a wire to a substrate, comprising the following steps:

[0024] a. The bonding wire is led out from the cleaver;

[0025] b. driving the riving knife to extend relative to the frame in the first direction by the first actuating unit and bonding the wire;

[0026] c. After bonding is completed, the second actuating unit drives the cutter toward the wire along the first direction to cut off the bonded wire;

[0027] d. After the cutting is completed, the first actuating unit drives the riving knife to retract into the frame along the first direction, and the second actuating unit drives the cutter away from the wire along the first direction.

[0028] In one or more embodiments, in step c, while the cutter is caused to cut the bonded wires, the first actuating unit drives the riving knife to retract into the frame along the first direction.

[0029] The beneficial effects of the present invention are:

[0030] However, with this welding head assembly, this bonding machine, and this bonding method, the cutter does not perform tangents by overpressure, but is directly driven by a second actuator unit. This reduces the load on the drive, shortens the distance from the drive to the execution, and increases the control accuracy of the cutter's cutting operation. It can be understood that the original control method can be compared to an arm controlling a finger, which requires the entire system to move during driving, and the accuracy at the end of the system will be affected; the method provided by this application can be compared to directly controlling the finger, and the control accuracy will be more convenient and accurate. At the same time, for this application, since the first actuator unit controls the splitting knife alone and the second actuator unit controls the cutter alone, the splitting knife drive originally only provides a downward welding force, but can now also achieve the lifting action of the splitting knife by applying a reverse force. During the lifting process, both the cutter and the splitting knife can be lifted simultaneously by separate drives, so the tangent efficiency can be increased by half.

[0031] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

[0032] Summary of the Figures

[0033] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0034] FIG1 shows a schematic diagram of a bonding head assembly in a conventional bonding machine;

[0035] FIG2 shows a side view of a conventional welding head assembly;

[0036] FIG3 shows a schematic diagram of an embodiment of the welding head assembly;

[0037] FIG4 shows a schematic diagram of a welding head assembly according to a second embodiment of the present invention.

[0038] Specific embodiments of the present invention

[0039] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0041] To improve the efficiency and quality of a bonding machine, a bonding head assembly is provided according to some embodiments of the present application. The bonding head assembly mentioned herein is also referred to as a wire bond head in some literature. This bonding head assembly is used in a bonding machine and serves as the working part of the bonding machine during bonding.

[0042] FIG3 shows a schematic diagram of a welding head assembly according to an embodiment of the present invention. The welding head assembly includes a frame 1 , a wrecking knife 2 , a first actuating unit 3 , a second actuating unit 4 and a cutting knife 5 .

[0043] The frame 1 is the main component of the welding head assembly, which plays the role of supporting and accommodating other components. It can be a frame or shell with any structure.

[0044] The splitting knife 2 is a working component in the welding head assembly, and is used to weld and connect the wire to be bonded and the substrate during the bonding operation. The inside of the splitting knife 2 has a lead hole, and the wire to be bonded can be guided from the fixed end 21 of the splitting knife 2 to the working end 22 through the lead hole. The working end 22 of the splitting knife 2 is the free end of the splitting knife 2 and is the working head in the welding head assembly. The working end 22 applies heat, pressure and ultrasonic vibration to the wire to weld it to the substrate. The splitting knife 2 is connected to the frame 1, and in the connected state, the splitting knife 2 can move relative to the frame 1 along a first direction a. In a specific embodiment, as shown in Figure 3, the fixed end 21 of the splitting knife 2 has a connecting section 23, which is connected to the frame 1 via the connecting section 23.

[0045] The first actuating unit 3 is fixed to the frame 1 and is in transmission connection with the riving knife 2. When the first actuating unit 3 is actuated, it can drive the riving knife 2 to move relative to the frame 1 along the first direction a.

[0046] The second actuating unit 4 is fixed on the frame 1 . For example, in the embodiment shown in the figures, the second actuating unit 4 is fixed on a side surface of the frame 1 .

[0047] Cutter 5 is the component in the welding head assembly that cuts the wire. After bonding is complete, the two ends of the wire are welded to the substrate. At this point, cutter 5 is required to cut the wire that has emerged from the lead-in hole of splitter 2, allowing splitter 2 to continue bonding at the next station. It will be understood that cutter 5 has a blade that is used to cut the wire by applying external force. Cutter 5 is connected to frame 1 via a second actuator unit 4, meaning that cutter 5 itself is not directly connected to frame 1. Furthermore, second actuator unit 4 is in transmission connection with cutter 5, allowing it to move relative to frame 1 in a first direction a when actuated.

[0048] The first direction a is defined as follows: during bonding, when the bonding head assembly moves along the first direction a, it can approach or move away from the workpiece to be bonded. That is, during bonding, the movement of the cleaver 2 along the first direction a can approach and press against the substrate to be bonded. After bonding is completed, the movement of the cutter 5 along the first direction a can cause the blade to sever the wire.

[0049] On the other hand, according to some embodiments of the present application, a bonding machine is further provided, which includes a bonding head assembly as described in one or more embodiments of the present application.

[0050] In another aspect, according to some embodiments of the present application, a bonding method is provided, which uses a bonding machine as described in one or more embodiments of the present application to bond a wire to a substrate. Referring to FIG3 , the bonding method includes the following steps:

[0051] Step a. Lead the wire to be bonded from the cleaver 2. Specifically, lead the wire from the lead hole of the cleaver 2. In a specific embodiment, the wire is wound on a roller, and the wire is fed by the rotation of the roller.

[0052] Step b. The first actuating unit 3 drives the riving blade 2 to extend relative to the frame 1 in the first direction a, thereby bonding the wire. In the illustrated embodiment, the frame 1 has an opening or is open at the bottom, and the riving blade 2 is supported on the inner side of the frame 1. When the first actuating unit 3 is actuated, the riving blade 2 is driven to extend from the bottom of the frame 1. Of course, in other embodiments, the riving blade 2 is not positioned within the frame 1. The extension of the riving blade 2 relative to the frame 1 in the first direction a means that the riving blade 2 moves relative to the frame 1 toward the substrate, thereby bonding the wire extending from the lead hole to the substrate.

[0053] Step c. After bonding is completed, the second actuating unit 4 drives the cutter 5 to move toward the wire along the first direction a to cut the bonded wire. It is understood that bonding is completed when the cutter 2 completes welding of both ends of the wire to the substrate.

[0054] Step d. After the cutting is completed, the first actuating unit 3 drives the riving knife 2 to retract into the frame 1 along the first direction a, and the second actuating unit 4 drives the cutter 5 away from the wire along the first direction a.

[0055] The bonding process of one section of wire and the substrate is completed by steps a to d above, and the bonding of multiple sections of wire and the substrate is completed by repeating steps a to d above.

[0056] In existing bonding machine bond head assemblies, the severing operation is achieved by generating overpressure between the cutter and the wrecking blade, as mentioned in the background. Therefore, the wrecking blade and the cutter must be lifted together as a single unit. Consequently, the cutter must be detached first, followed by the wrecking blade being lifted and detached from the bond wire, resulting in low efficiency. Furthermore, controlling the cutter's severing operation requires actuating the entire frame to achieve the severing operation. This imposes a heavy load on the drive, a long distance from the actuator, and low control accuracy.

[0057] However, with this welding head assembly, bonding machine, and bonding method, the cutter 5 does not cut the wire by overpressure, but is instead directly driven by a second actuator unit. This reduces the load on the drive, shortens the distance between drive and execution, and increases the control accuracy of the cutter 5's cutting operation. It can be understood that the original control method can be compared to an arm controlling a finger, requiring the entire system to move during actuation, which affects the accuracy at the end of the system. The method provided by this application can be compared to directly controlling the finger, making the control accuracy more convenient and precise. Furthermore, in this application, since the first actuator unit 3 independently controls the splitting knife 2 and the second actuator unit 4 independently controls the splitting knife 5, the splitting knife 2 drive, which originally only provided downward welding force, can now also achieve a lifting action by applying a reverse force. This allows both the cutter 5 and the splitting knife 2 to be lifted simultaneously during the lifting process through independent actuation, thereby increasing the cutting efficiency by half.

[0058] In the description of the embodiments of this application, the technical terms "first" and "second," such as "first actuating unit 3" and "second actuating unit 4," are used solely to distinguish different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of this application, "plurality" means more than two, unless otherwise specifically defined.

[0059] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0060] In some embodiments of the welding head assembly, the riving blade 2 is elastically connected to the frame 1 to allow the riving blade 2 to move relative to the frame 1 in a first direction a. Furthermore, in one specific embodiment, the riving blade 2 is elastically connected to the frame 1 via a spring plate 6. When the first actuating unit 3 is actuated, the spring plate 6 elastically deforms, allowing the riving blade 2 to move relative to the frame 1 in the first direction a. It will be appreciated that in other embodiments differing from the illustrated structure, the riving blade 2 can be made movable relative to the frame in the first direction a by coupling the riving blade with the frame, for example, via a slide rail. Compared to other approaches, elastically connecting the riving blade 2 to the frame 1 via the spring plate 6 eliminates friction between the riving blade 2 and the frame during movement in the first direction a when the first actuating unit 3 is actuated, resulting in smoother movement. Furthermore, upon release of external force, the riving blade 2 can be quickly reset by the elastic return of the spring plate 6.

[0061] In some embodiments of the present welding head assembly, the wedge blade 2 is a wedge-shaped wedge blade, and the present welding head assembly is capable of performing wedge welding.

[0062] In some embodiments of the present welding head assembly, the welding head assembly further includes a third actuating unit 7, which is connected to the frame transmission 1 and, when activated, can drive the entire frame 1 to move in a first direction a. It will be appreciated that when the third actuating unit 7 is activated, the frame 1 and the riving knife 2 and cutter 5 connected thereto synchronously follow the frame 1 in the first direction a. The third actuating unit 7 is used to rapidly move the riving knife 2 and cutter 5 toward or away from the object to be bonded.

[0063] In some embodiments of the welding head assembly, the first actuating unit 3 and / or the second actuating unit 4 and / or the third actuating unit 7 are linear motors. In some other suitable embodiments, the first actuating unit 3 and / or the second actuating unit 4 and / or the third actuating unit 7 are other motors or cylinders that can drive the driven components to move in a straight line. The use of a linear motor as an actuating unit has the characteristics of fast response speed and high actuation accuracy. In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the previous and subsequent associated objects are in an "or" relationship.

[0064] In some embodiments of the present welding head assembly, in the initial state, the splitting knife 2 and the cutter 5 extend the same distance relative to the bottom surface of the frame 1, that is, the free end of the splitting knife 2 is flush with the free end of the cutter 5. Figure 2 shows a side view of a conventional welding head assembly. In conventional welding head assemblies, the splitting knife 91 and the cutter 92 cannot be made flush. Typically, the splitting knife 91 extends further than the cutter 92 to achieve overpressure. In the present welding head assembly, however, since the splitting knife 2 and the cutter 5 are driven by different actuating units, their free ends can be configured to be flush, further improving the efficiency of bonding and cutting operations.

[0065] In some embodiments of the present welding head assembly, in the initial state, the splitting knife 2 and the cutter 5 are arranged roughly in parallel, and the free ends of the splitting knife 2 and the cutter 5 are arranged close to each other, so that the cutter 5 can cut the bonded wire from the free end close to the splitting knife 2.

[0066] Figure 4 shows a schematic diagram of a second embodiment of the welding head assembly. In this second embodiment, a cutter spring 8' is provided between the cutter 5' and the frame 1'. During a wire cutting operation in this second embodiment, the cutter spring 8' guides the cutter 5' toward the wire, generating a certain component with respect to the first direction a, thereby enabling the cutter 5' to cut the wire with different cut shapes.

[0067] In some embodiments of the present welding head assembly, a guide assembly is provided between the cutter 5 and the frame 1. This guide assembly enables the second actuator unit 4 to drive the cutter 5 to move in a direction with a component relative to the first direction a, thereby enabling the cutter 5 to cut the wire with different cut shapes. In some specific embodiments, the guide assembly may be a connecting rod assembly or a hinge.

[0068] In some embodiments of the bonding method, in step c, while the cutter 5 cuts the bonded wire, the first actuating unit 4 drives the riving knife 2 to retract into the frame 1 along the first direction a, thereby further improving the efficiency of the bonding process.

[0069] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0070] It should be understood that “along” a certain direction means having at least a component in the direction, preferably, the angle with the direction is within 15°, more preferably, the angle is within 10°.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A bonding head assembly for a bonder, characterized in that, it includes: a frame; a capillary, movably connected to the frame in a first direction; a first actuating unit, fixed to the frame and drivingly connected to the capillary, capable of driving the capillary to move relative to the frame in the first direction when actuated; a second actuating unit, fixed to the frame; and a cutter, connected to the frame through the second actuating unit, the second actuating unit being drivingly connected to the cutter, capable of driving the cutter to move relative to the frame in the first direction when actuated; wherein, during bonding, when the bonding head assembly moves in the first direction, it can approach or move away from the workpiece to be bonded.

2. The bonding head assembly according to claim 1, characterized in that, the capillary is elastically connected to the frame to allow the capillary to move relative to the frame in the first direction.

3. The bonding head assembly according to claim 2, characterized in that, the capillary is elastically connected to the frame through a spring piece.

4. The bonding head assembly according to claim 1, characterized in that, a cutter spring piece is provided between the cutter and the frame.

5. The bonding head assembly according to claim 1, characterized in that, a guiding assembly is provided between the cutter and the frame, and when the second actuating unit is actuated, the guiding assembly enables the moving direction of the cutter to have a component relative to the first direction.

6. The bonding head assembly according to claim 1, characterized in that, the capillary is a wedge-shaped capillary.

7. The bonding head assembly according to claim 1, characterized in that, it further includes a third actuating unit, the third actuating unit being drivingly connected to the frame, capable of driving the entire frame to move in the first direction when actuated.

8. The bonding head assembly according to claim 7, characterized in that, the first actuating unit and / or the second actuating unit and / or the third actuating unit is a linear motor.

9. The bonding head assembly according to claim 1, characterized in that, in the initial state, the capillary and the cutter extend the same distance relative to the bottom surface of the frame.

10. A bonder, characterized in that, it includes the bonding head assembly according to any one of claims 1 to 9.

11. A bonding method, characterized in that, using the bonder according to claim 10 to bond a wire and a substrate, including the following steps: a. Let the wire to be bonded be led out from the capillary; b. Drive the capillary to extend relative to the frame in the first direction through the first actuating unit and bond the wire; c. After bonding is completed, drive the cutter to move towards the wire in the first direction through the second actuating unit to cut the wire that has completed bonding; d. After cutting is completed, drive the capillary to retract into the frame in the first direction through the first actuating unit and drive the cutter to move away from the wire in the first direction through the second actuating unit.

12. The bonding method according to claim 11, characterized in that, In step c, while the cutter cuts the wire that has completed bonding, the first actuating unit drives the wedge to retract into the frame along the first direction.

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