Welding head assembly and ultrasonic wedge welder

Abstract

The utility model belongs to the technical field of semiconductor packaging equipment, and relates to a welding head assembly which comprises an energy converter and a chopper, one end of the energy converter is provided with a chopper hole, the chopper is fixed in the chopper hole, the energy converter is further provided with at least two fasteners, the fasteners abut against the chopper in the fixing process, and the energy converter is connected with the chopper. The chopper is in linear contact with the inner wall of the chopper hole; the utility model further relates to an ultrasonic wedge welding machine. According to the technical scheme, the chopper can be fastened through at least two fastening pieces, meanwhile, the chopper makes linear contact with the inner wall of the chopper hole, long-distance and continuous constraint is formed, the clamping rigidity of the fastening pieces is improved so that welding force can be borne, and the service life of the chopper is prolonged. The problems that due to the facts that the foremost end of a fastener is uneven or a locking hole for fixing the chopper is not perpendicular to the chopper hole, inclination and gaps exist between the chopper and the chopper hole are solved, it is guaranteed that the installing position, the installing angle and the perpendicularity of the chopper are kept stable in the welding process, and the reliability and stability of welding are improved.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor packaging equipment, and more specifically, to a welding head assembly and an ultrasonic wedge welding machine. Background Art

[0002] In an ultrasonic wedge welder, the welding head assembly is the working part for bonding, which includes a transducer and a wedge. The transducer converts the electrical signal from the sound source into high-frequency vibration and transmits it to the wedge. The wedge has a lead channel inside. After the metal wire for welding is led out through the channel inside the wedge, the working part of the free end of the wedge heats, presses and vibrates the metal wire at high frequency to weld it to the substrate to complete the bonding process.

[0003] At present, in ultrasonic wedge welding machines, the splitting knife is fixed in the transducer by placing the splitting knife in a splitting knife hole at one end of the transducer and fixing it by a fastener. However, the splitting knife is fixed by a single fastener. Because the front end of the fastener is uneven or the locking hole for fixing the splitting knife is not perpendicular to the splitting knife hole, there will be an inclination and gap between the splitting knife and the splitting knife hole, which will affect the transmission of ultrasonic vibration and cause unreliable welding. Utility Model Content

[0004] The technical problem to be solved by the technical solution of the present application is that the existing welding head assembly may cause the chopper and the chopper hole to be tilted and have a gap because the front end of the fastener is uneven or the locking hole for fixing the chopper is not perpendicular to the chopper hole, thereby affecting the transmission of ultrasonic vibration and causing unreliable welding.

[0005] In order to solve the above technical problems, the embodiment of the present application provides a welding head assembly, which adopts the following technical solution:

[0006] The welding head assembly includes a transducer and a splitting knife. A splitting knife hole is provided at one end of the transducer. The splitting knife is fixed in the splitting knife hole. At least two fasteners are also provided on the transducer. When fixed, the fasteners are against the splitting knife, so that the splitting knife is in linear contact with the inner wall of the splitting knife hole.

[0007] Furthermore, the arrangement direction of the fasteners is the same as the length direction of the contact line between the riving knife and the riving knife hole.

[0008] Furthermore, the distance D between the two fasteners satisfies the following conditions:

[0009] D>3mm.

[0010] Furthermore, the distance D between the two fasteners further satisfies the following conditions:

[0011] λ / 4>D

[0012] Among them, λ is the amplitude length of the wedge vibration.

[0013] Further, the pressure F applied by the fastener on the wedge satisfies the following formula:

[0014] F*P b =2π*T*μ

[0015] Among them, P b is the thread pitch;

[0016] T is the moment, T = 5kgf·cm;

[0017] μ is the coefficient, μ=0.144.

[0018] Furthermore, a fastening plane is provided at one end of the riving knife, and the fastener abuts against the fastening plane when being fixed.

[0019] Furthermore, the transducer is provided with a locking hole which is in communication with the riving knife hole, and the fastener extends into the riving knife hole through the locking hole and abuts against the riving knife.

[0020] Furthermore, the depth H of the locking hole satisfies the following conditions:

[0021] H<1 / 12*(nλ)

[0022] Where nλ is the resonance length Lre.

[0023] Furthermore, the fastener is configured as a top screw, and the locking hole is configured as a screw hole.

[0024] Furthermore, the diameter of the fastener is 3 mm.

[0025] In order to solve the above technical problems, the technical solution of the present application also provides an ultrasonic wedge welding machine, which adopts the following technical solution: the ultrasonic wedge welding machine includes the welding head assembly.

[0026] Compared with the prior art, the technical solution of the present application mainly has the following beneficial effects: the splitting knife described in the present application is fastened by at least two fasteners, and at the same time, the splitting knife is in linear contact with the inner wall of the splitting knife hole to form a long-distance and continuous constraint, thereby improving the clamping rigidity of the fastener to withstand the welding force, avoiding the occurrence of problems such as inclination and gap between the splitting knife and the splitting knife hole due to unevenness of the front end of the fastener, or non-perpendicularity between the locking hole for fixing the splitting knife and the splitting knife hole, thereby ensuring that during the welding process, the installation position, installation angle and verticality of the splitting knife remain stable, thereby improving the reliability and stability of welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the scheme of the present application, a brief introduction is given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 It is a schematic diagram of the structure of the welding head assembly;

[0029] Figure 2 It is an exploded view of the welding head assembly;

[0030] Figure 3 is a cross-sectional view of the welding head assembly;

[0031] Figure 4 yes Figure 3 A is an enlarged schematic diagram;

[0032] Figure 5 is a schematic diagram of the structure of the transducer;

[0033] Figure 6 It is a schematic diagram of the structure of the fastener.

[0034] Figure numerals: 1, transducer; 11, riving knife hole; 12, locking hole; 2, riving knife; 21, fastening plane; 3, fastener. DETAILED DESCRIPTION

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of the application 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 drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0036] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0037] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0038] Please refer to the attached Figure 1-Figure 6 An embodiment of the present application provides a welding head assembly, including a transducer 1 and a splitting knife 2, wherein a splitting knife hole 11 is provided at one end of the transducer 1, and the splitting knife 2 is fixed in the splitting knife hole 11. At least two fasteners 3 are also provided on the transducer 1. When fixed, the fasteners 3 abut against the splitting knife 2, so that the splitting knife 2 is in linear contact with the inner wall of the splitting knife hole 11.

[0039] The splitting knife 2 in the present application is fastened by at least two fasteners 3, and at the same time, the splitting knife 2 is in line contact with the inner wall of the splitting knife hole 11, forming a long-distance and continuous constraint, thereby improving the clamping rigidity of the fastener 3 to withstand the welding force, avoiding the occurrence of problems such as the splitting knife 2 and the splitting knife hole 11 being tilted and having a gap due to the front end of the fastener 3 being uneven, or the locking hole for fixing the splitting knife 2 being not perpendicular to the splitting knife hole 11, thereby ensuring that during the welding process, the installation position, installation angle and verticality of the splitting knife 2 remain stable, thereby improving the reliability and stability of welding.

[0040] As attached Figure 1-Figure 4 As shown, further, the arrangement direction of the fastener 3 is the same as the length direction of the contact line between the riving knife 2 and the riving knife hole 11. The fastener 3 is arranged relative to the contact line between the riving knife 2 and the riving knife hole 11, that is, the force application point and the contact line are located at both ends of the fastener 3, and at least two fasteners 3 form at least two force application points on the riving knife 2 at the other end opposite to the contact line, thereby improving the clamping rigidity and clamping stability of the fastener 3 on the riving knife 2, ensuring that the installation position, installation angle and verticality of the riving knife 2 remain stable, and easy to process and realize.

[0041] Furthermore, the arrangement direction of the fasteners 3 is the direction of the length of the chopper hole 11, and the axes of all the fasteners 3, the axes of the fasteners 3, and the contact lines of the chopper 2 and the chopper hole 11 are all on the same vertical plane, so that the fastening of the chopper 2 is distributed in a centrally symmetrical manner. The line contact plus the fixing method of at least two force application points can achieve uniform clamping force for the chopper 2, further ensuring the stability of the clamping effect of the chopper 2. At the same time, the line contact plus at least two force application points can also increase the number of channels for ultrasonic transmission accordingly, providing high-efficiency ultrasonic transmission and excellent ultrasonic energy transmission channels, further ensuring the welding quality, and the number of the fasteners 3 can be installed according to actual conditions to meet the needs of different power welding, and the welding head assembly has strong adaptability.

[0042] As attached Figure 1-Figure 4 As shown, further, the distance D between the two fasteners 3 satisfies the following conditions:

[0043] D>3mm.

[0044] The distance D between the two fasteners 3 is not less than 3 mm, which can prevent the distance D from being too close and causing the two adjacent fasteners 3 to affect each other. The transducer 1 is provided with a locking hole 12 that communicates with the riving knife hole 11. The fastener 3 extends into the riving knife hole 11 through the locking hole 12 and abuts against the riving knife 2, and prevents the distance between the two adjacent locking holes 12 from being too small, causing the structure between the two locking holes 12 to be broken or deformed when the transducer 1 is used.

[0045] As attached Figure 1-Figure 4 As shown, further, the distance D between the two fasteners 3 further satisfies the following conditions:

[0046] λ / 4>D

[0047] Among them, λ is the amplitude length of the wedge vibration.

[0048] The amplitude length of the wedge vibration is calculated by the following formula:

[0049] nλ=mi(RC / ω) 1 / 2

[0050] Where: nλ is the resonance length Lre;

[0051] λ is the amplitude length of the wedge vibration;

[0052] n is the number of wavelengths transmitted by ultrasonic waves on the splitter in actual working conditions, n = 3;

[0053] mi is the reference constant;

[0054] R is the radius of the wedge;

[0055] C is the length of the longitudinal wave, and the transmission speed of the ultrasonic wave in the stainless steel horn is 5200m / s;

[0056] ω is the angular velocity, ω=2πf;

[0057] Taking the design of 60KHz as an example, the riving knife 2 can be regarded as a horn of bending vibration.

[0058] The reference constant mi can be calculated by the following formula:

[0059] cos(mi)cosh(mi)=1.

[0060] The order i=5 is selected and mi=14.137 is calculated.

[0061] In this embodiment, the radius R of the splitting cutter is 1.585 mm, from which it can be calculated that the resonance length Lre=66 mm; and the sound wave is transmitted on the splitting cutter in actual working conditions as 3 wavelengths, so the amplitude wavelength λ of the splitting cutter vibration is 22 mm.

[0062] In summary, the distance D satisfies the following conditions: 5.5mm>D

[0063] Since the distance D between the two fasteners 3 mentioned above needs to satisfy D>3mm, the distance D between the two fasteners 3 satisfies 5.5>D>3mm. Therefore, the distance D between the two fasteners 3 is in the range of 3-5.5mm, preferably 4mm and 5mm, which can not only avoid the distance D being too small to affect the transducer 1, but also improve the clamping stiffness and clamping stability of the fastener 3 on the splitting knife 2, ensure that the installation position, installation angle and verticality of the splitting knife 2 remain stable, so that the transducer 1 can effectively output ultrasound through the splitting knife 2 and act on the metal wire to weld it to the substrate to complete the bonding process.

[0064] As attached Figure 1-Figure 4 As shown, further, the pressure F applied by the fastener 3 on the riving knife 2 satisfies the following formula:

[0065] F*P b =2π*T*μ

[0066] Among them, P b is the thread pitch;

[0067] T is the moment, T = 5kgf·cm;

[0068] μ is the coefficient, μ=0.144.

[0069] As attached Figure 1-Figure 4 As shown, further, the fastener 3 is configured as a top screw, the locking hole 12 is configured as a screw hole, and the diameter of the fastener 3 is 3 mm. Therefore, taking a top screw with a diameter of 3 mm as an example, the pitch P b =0.5mm, so it is calculated that F=90.4kgf, and the pressure F applied by each fastener 3 on the riving knife 2 is the same, so that the clamping force on the riving knife 2 is uniform, and the stability of the clamping effect of the riving knife 2 is further improved.

[0070] Furthermore, a fastening plane 21 is provided at one end of the splitting knife 2, and the fastener 3 is against the fastening plane 21 when fixed. The contact area between the splitting knife 2 and the fastener 3 is further increased. Of course, the splitting knife hole 11 can also be set as a special-shaped hole to improve the clamping rigidity of the fastener 3 to withstand the welding force, avoid the front end of the fastener 3 is uneven, or the locking hole for fixing the splitting knife 2 is not perpendicular to the splitting knife hole 11, resulting in the occurrence of problems such as tilt and gap between the splitting knife 2 and the splitting knife hole 11, and ensure that during the welding process, the installation position, installation angle and verticality of the splitting knife 2 remain stable, thereby improving the reliability and stability of welding.

[0071] As attached Figure 2 , Figure 4-Figure 5 As shown, further, the transducer 1 is provided with a locking hole 12 communicated with the riving knife hole 11, and the fastener 3 extends into the riving knife hole 11 through the locking hole 12 and abuts against the riving knife 2, so that the top screw is conveniently screwed in to form at least two force application points on the riving knife 2, thereby improving the clamping stiffness and clamping stability of the fastener 3 on the riving knife 2, ensuring that the installation position, installation angle and verticality of the riving knife 2 remain stable, and easy to process and realize.

[0072] As attached Figure 2 , Figure 4-Figure 5 As shown, further, the depth H of the locking hole 12 satisfies the following conditions:

[0073] H<1 / 12*(nλ)

[0074] Where nλ is the resonance length Lre.

[0075] From the above calculation, the resonance length Lre = 66mm, so H < 5.5mm. That is, the distance from the outer surface of the free end of the transducer 1 to the wedge hole 11. Of course, H needs to be greater than 0, so that the fastener 3 is conveniently fixed in the locking hole 12. The appropriate depth H of the locking hole 12 can ensure that the fastener 3 has enough thread length to be embedded in the transducer 1, thereby providing sufficient fastening force and connection strength, and improving assembly accuracy.

[0076] Based on the above-mentioned welding head assembly, the embodiment of the present application also provides an ultrasonic wedge welding machine, including the welding head assembly. The splitting knife 2 in the present application is fastened by at least two fasteners 3, and at the same time, the splitting knife 2 is in line contact with the inner wall of the splitting knife hole 11, forming a long-distance and continuous constraint, improving the clamping stiffness of the fastener 3 to withstand the welding force, avoiding the front end of the fastener 3 being uneven, or the locking hole for fixing the splitting knife 2 being not perpendicular to the splitting knife hole 11, resulting in the occurrence of problems such as tilt and gap between the splitting knife 2 and the splitting knife hole 11, ensuring that during the welding process, the installation position, installation angle and verticality of the splitting knife 2 remain stable, and improving the reliability and stability of welding.

[0077] Obviously, the embodiments described above are only some embodiments of the present application, rather than all embodiments. The preferred embodiments of the present application are given in the accompanying drawings, but they do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. Although the present application is described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific implementation methods, or to perform equivalent replacement of some of the technical features therein. Any equivalent structure made using the contents of the specification and drawings of this application, directly or indirectly used in other related technical fields, is similarly within the scope of patent protection of this application.

Claims

1. A welding head assembly, characterized in that: The invention comprises a transducer (1) and a riving knife (2), wherein a riving knife hole (11) is arranged at one end of the transducer (1), the riving knife (2) is fixed in the riving knife hole (11), and at least two fasteners (3) are also arranged on the transducer (1), and when fixed, the fasteners (3) abut against the riving knife (2), so that the riving knife (2) is in linear contact with the inner wall of the riving knife hole (11).

2. The welding head assembly according to claim 1, characterized in that: The arrangement direction of the fasteners (3) is the same as the length direction of the contact line between the riving knife (2) and the riving knife hole (11).

3. The welding head assembly according to claim 2, characterized in that: The distance D between the two fasteners (3) satisfies the following conditions: D>3mm.

4. The welding head assembly according to claim 3, characterized in that: The distance D between the two fasteners (3) further satisfies the following conditions: λ / 4>D Among them, λ is the amplitude length of the wedge vibration.

5. The welding head assembly according to claim 1, characterized in that: The pressure F exerted by the fastener (3) on the riving knife (2) satisfies the following formula: F*Pb=2π*T*μ Among them, P b is the thread pitch; T is the moment, T = 5kgf·cm; μ is the coefficient, μ=0.

144.

6. The welding head assembly according to claim 1, characterized in that: A fastening plane (21) is provided at one end of the riving knife (2), and the fastening member (3) abuts against the fastening plane (21) when being fixed.

7. The welding head assembly according to claim 1, characterized in that: The transducer (1) is provided with a locking hole (12) which is in communication with the riving knife hole (11); the fastener (3) extends into the riving knife hole (11) through the locking hole (12) and abuts against the riving knife (2).

8. The welding head assembly according to claim 7, characterized in that: The depth H of the locking hole (12) satisfies the following conditions: H<1 / 12*(nλ) Where nλ is the resonance length Lre.

9. The welding head assembly according to any one of claims 7-8, characterized in that: The fastener (3) is configured as a top screw, and the locking hole (12) is configured as a screw hole.

10. An ultrasonic wedge welding machine, characterized in that: Comprising the welding head assembly according to any one of claims 1 to 9.

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