High-hardness Al-Mg bonded aluminum wire ultrasonic wedge and bonding structure

Abstract

The application discloses a high-hardness Al-Mg bonded aluminum wire ultrasonic wedge and a bonding structure. The high-hardness Al-Mg bonded aluminum wire ultrasonic wedge and the bonding structure comprise: a high-hardness Al-Mg bonded aluminum wire with a tensile strength greater than or equal to 350 MPa and a Vickers hardness of 20-40; an ultrasonic wedge with a center threading hole and a lead slot at the end, the bottom surface of the slot being processed with a micro-nano grid rough texture; an asymmetric double chamfer structure with an inner chamfer of 45° and an outer chamfer of 30° arranged at the lower pressing edge of the ultrasonic wedge; and a bonding structure formed by pressing the high-hardness Al-Mg bonded aluminum wire through the ultrasonic wedge, and the upper surface of the pressing mark interface being distributed with reverse micro-protrusions. The application can realize effective coupling transmission of high-frequency kinetic energy, avoid interface slip failure, completely eliminate the hidden danger of brittle fracture of the high-toughness alloy wire under pressure, and guarantee the high connection reliability and mechanical stability of the semiconductor packaging device under harsh working environment.

Description

Technical Field

[0001] This application discloses a high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure. Specifically, it relates to a high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and corresponding bonding structure that can adapt to the working characteristics of high-strength and high-toughness wires. Background Technology

[0002] In the current high-end electronics manufacturing sector, with the rapid development of high-power semiconductor devices, high-frequency radio frequency modules, and high-reliability electronic components for aerospace applications, the stability and harsh operating conditions of internally packaged interconnect systems are facing challenges. Traditional semiconductor wire bonding processes have long used soft pure aluminum wire or lightly alloyed aluminum wire as interconnect materials. However, these traditional soft leads have inherent physical limitations: insufficient tensile strength, making them prone to fatigue fracture under long-term thermomechanical stress cycles or high-frequency vibration environments; and poor resistance to electrochemical corrosion and salt spray corrosion, making them unsuitable for prolonged use under specific harsh operating conditions.

[0003] To address the aforementioned shortcomings, the industry has gradually explored the use of copper or other special precious metals as alternatives. However, this not only increases manufacturing costs but also raises the bar for existing mature substrate metallization processes due to material compatibility issues. Against this backdrop, high-hardness aluminum alloys with high strength and high corrosion resistance, especially multi-element composite aluminum alloy bonding wires with added elements such as magnesium and scandium, have become a highly promising alternative due to their lightweight, excellent electrical properties, and strong environmental resistance.

[0004] However, when high-hardness Al-Mg alloy wires were actually introduced into the ultrasonic bonding production line, a series of technical problems were exposed. Compared with traditional pure aluminum wire, the hardness and tensile strength of high corrosion-resistant alloy wires are increased several times. If existing conventional ultrasonic crimping cutters designed for soft materials are directly used for crimping operations, it usually leads to low efficiency of ultrasonic high-frequency mechanical energy transfer, and the indenter head is prone to ineffective relative slippage on the surface of hard wire. In order to compensate for the energy loss caused by slippage, a larger static crimping force and stronger ultrasonic power are required, which will cause excessive mechanical cutting damage to the hard lead wire by the cutting edge of the cutter, resulting in frequent microcracks at the root of the bonding point. In addition, the plastic rheological behavior of hard materials under pressure is extremely difficult to control, which can easily cause either insufficient deformation at the indentation site leading to poor soldering, or excessive overflow leading to short circuits and failure of interfacial bonding. Summary of the Invention

[0005] This application provides a high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure. Through the synergy of micro-nano-level gripping structure and macro-morphological yielding design, it solves the technical problems of poor energy coupling, easy root brittleness and difficulty in indentation forming of high-strength and tough alloy wires in semiconductor bonding, and achieves the unity of high mechanical strength and corrosion resistance in packaged devices.

[0006] The following technical solution is adopted in this application:

[0007] This application provides a high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure, including:

[0008] The high-hardness Al-Mg bonded aluminum wire has an initial wire diameter, a tensile strength greater than or equal to 350 MPa, and a Vickers hardness between 20 and 40.

[0009] An ultrasonic cleaver is used to crimp the high-hardness Al-Mg bonded aluminum wire. The ultrasonic cleaver has a central wire-passing hole and an arc-shaped wire-leading groove at its end. The bottom surface of the arc-shaped wire-leading groove is processed with a micro-nano-level mesh-like rough texture, the depth of which is limited to between 0.5 μm and 1.2 μm. The downward pressing edge of the ultrasonic cleaver is configured with an asymmetric double-bevel structure, which includes an inner bevel and an outer bevel. The inner bevel is defined between the bottom of the central wire-passing hole and the arc-shaped wire-leading groove at an angle of 45°, and the outer bevel is defined between the outer edge of the arc-shaped wire-leading groove and the sidewall of the ultrasonic cleaver at an angle of 30°.

[0010] The high-hardness Al-Mg bonded aluminum wire is formed into a bonded structure after being pressed by the ultrasonic cleaver. The upper surface of the indentation interface at the bond root of the bonded structure is distributed with reverse micro-protrusions that match the micro-nano-scale mesh-like rough texture. The indentation deformation width of the bonded structure is 1.5 to 2.2 times the initial wire diameter.

[0011] As a further preferred embodiment of the present application, the micro-nano-scale mesh-like rough texture specifically comprises multiple truncated pyramidal protruding micro-units arranged in a tightly matrix array. A network of chip discharge channels, orthogonally distributed between adjacent truncated pyramidal protruding micro-units, is naturally formed, and the bottom of the chip discharge channel network has a flat-bottom structure.

[0012] The top surface of each truncated pyramid-shaped protruding micro-unit is a square flat contact surface with a side length between 0.8 μm and 1.5 μm, and its bottom surface is a square base surface with a side length between 2.0 μm and 3.5 μm. The top surface and the bottom surface are connected by four inclined sidewalls to form a trapezoidal shape, and the inclined sidewalls form an angle of 60° to 75° with the bottom surface. The center-to-center distance between two adjacent truncated pyramid-shaped protruding micro-units is set between 3.0 μm and 5.0 μm. The total area of ​​the square flat contact surfaces accounts for 35% to 55% of the total projected area of ​​the bottom surface of the arc-shaped lead groove.

[0013] As a core auxiliary design to enhance the strength of the lead root, the ultrasonic chopper also has a concealed annular stress relief microcavity inside. This annular stress relief microcavity is machined along the circumference at the physical intersection boundary between the lower end wall of the central threading hole and the inner chamfer surface, and is configured as an inwardly recessed spatial structure.

[0014] Further specifying, the radial penetration depth of the microcavity into the sidewall of the wire-passing hole is set to 8% to 12% of the initial wire diameter, and the axial height extending vertically is set to 15% to 20% of the initial wire diameter. In the formed bonded state, a chamfered reinforcing rib encapsulating the rigid base material is formed above the lead root. This chamfered reinforcing rib is solidified from an alloy material that undergoes intense rheological changes during the bonding compression stage and is forcibly extruded into the microcavity. Its outer contour adheres to the inner wall of the microcavity, forming a self-locking anchoring ring structure. Through this upward material flow mechanism, the final root thickness of the bonded structure is guaranteed to be greater than 85% of the initial wire diameter.

[0015] From the perspective of interface micro-bonding, the reverse micro-protrusions and the micro-nano-scale mesh-like rough texture at the end of the ultrasonic chopper interlock with each other and form a deeply coupled interlocking interface layer after ultrasonic friction. This interlocking interface layer exhibits a wavy dense bonding band with continuous arrangement characteristics on its cross-section.

[0016] In addition, to optimize mechanical transmission, the first transition end face of the inner chamfer and the straight wall of the central wire hole are smoothly connected through a first arc surface, and the second transition end face of the inner chamfer and the curved surface of the arc-shaped lead groove are also smoothly connected through a second arc surface.

[0017] In terms of basic material selection and external design, the main body of the ultrasonic cleaver is made of high-wear-resistant materials such as fine-grained cemented carbide or alumina ceramic, and the working surface of the arc-shaped lead groove is additionally covered with a chemical anti-wear coating. The geometric radius of curvature of the arc-shaped lead groove in the transverse radial section is set to 0.6 to 0.85 times the initial diameter of the wire to be processed; at the same time, a tapered amplitude amplification and variable amplitude rod area that tapers inward along the longitudinal direction is provided above the outer surface of the ultrasonic cleaver.

[0018] This application also provides a semiconductor packaging device, including the high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and interconnect lead module formed by the bonding structure as described above.

[0019] Through a truncated pyramid micro-nano mesh structure of specific dimensions, it can not only penetrate the surface oxide layer under low contact pressure, but also lock the extremely hard aluminum alloy wire to the bottom surface of the blade, avoiding slippage caused by high-frequency vibration and improving the efficiency of energy conversion into plastic binding energy. The dynamic rheological pressure relief system constructed by the inner 45-degree and outer 30-degree asymmetric chamfer and the embedded annular release microcavity can induce the compressed metal material to form chamfered reinforcing ribs upward, providing a gripping fulcrum during the ultrasonic cycle, eliminating the tangential risk of easy breakage of hard wire, and providing a hardware foundation for high-reliability semiconductor packaging in special environments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the ultrasonic cleaver provided in an embodiment of the present invention.

[0021] Figure 2 This is a partial cross-sectional enlarged view of the end of the ultrasonic cleaver provided in an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the continuous operation process of the bonding cycle provided in an embodiment of the present invention.

[0023] Figure 4 This is an exploded diagram of the bonding principle and steps provided in the embodiments of the present invention.

[0024] Figure 5 This is a partial three-dimensional physical image of a semiconductor packaged device including the bonding structure provided in an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] In the diagram: 101-Ultrasonic chopper body, 102-High-hardness Al-Mg bonded aluminum wire, 103-Conical amplitude amplification variable rod area, 201-Central wire hole, 202-Arc-shaped lead groove, 204-Frusted pyramid-shaped protruding micro-unit, 205-Chip discharge channel network, 207-Annular stress relief micro-cavity, 208-Chamfered reinforcing rib, 401-Ultrasonic indenter, 402-Al wire, 403-Chip electrode, 404-Substrate electrode, 501-Semiconductor packaging device, 502-Lead arc, 2061-Inner chamfer, 2062-Outer chamfer. Detailed Implementation

[0027] The core structure and operating mechanism of this application will be described in detail and objectively below with reference to specific embodiments and corresponding drawings. It should be noted that the embodiments described herein are only representative of technical verification and illustration, and do not constitute a limitation on the scope of protection of the claims of this application.

[0028] This embodiment provides a hardware and interconnect system specifically optimized for high-hardness wires, namely a high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and the bonding structure formed therefrom. In this system, the core working material performing the connection task is a specially formulated high-hardness Al-Mg bonded aluminum wire 102. Figure 1 As shown, the ultrasonic cleaver body 101 serves as the main actuating mold, which fixes the aluminum wire onto the target pad through mechanical connection and pressing operations.

[0029] Key characteristics of the high-hardness Al-Mg bonded aluminum wire 102, the material used in the operation, were defined. This aluminum wire is based on a multi-component Al-Mg-Sc alloy substrate, with specific trace amounts of rare earth elements and transition metals added through a micro-alloying process. At the microcrystalline level, its material structure contains a densely distributed nanoscale L12 coherent precipitate structure. This unique coherent structure provides a strong dislocation pinning effect, enabling the alloy wire to maintain good electrical conductivity while achieving a significant improvement in mechanical properties.

[0030] The high-hardness Al-Mg bonded aluminum wire 102 has the following precisely controlled physicochemical and thermoelectric parameters: it has a high tensile yield strength, configured to be greater than or equal to 350 MPa; it maintains high toughness even under huge tensile forces, and its elongation is guaranteed to be greater than or equal to 15%; and, importantly, the Vickers hardness of its wire base material is stably distributed between 20 and 40, which makes its surface extremely hard compared to traditional pure aluminum wire.

[0031] Regarding thermal and electrical parameters, the aluminum wire has a phase transformation melting point of 660℃ and a material density of 2.70 g / cm³ at room temperature; its rigidity modulus, reflecting its elastic resistance to deformation, is as high as 27 kN / mm²; and its linear expansion coefficient is measured to be 25.3 × 10⁻⁶ within a standard environmental range of 20℃ to 30℃. -6 K -1 It exhibits excellent thermal conductivity, with a thermal conductivity of 230 W / m·K at 20℃. Regarding electrical conductivity, its bulk resistivity is 2.8 μΩ·cm, resulting in a relative conductivity of 64.0%. In practical applications, when the initial wire diameter of this alloy wire is drawn to the commonly used Φ25μm specification, its resistance per meter is precisely measured to be 57.1 Ω / m. Through the aforementioned multi-component composite microalloying design and the presence of the L12 reinforcing phase, this aluminum alloy bonding wire achieves over 1000 hours of corrosion resistance in standard high-concentration salt spray tests with no significant pitting corrosion on the surface, making it a viable alternative to expensive palladium-silver or platinum-silver corrosion-resistant materials.

[0032] When working with special wires with a hardness of 20-40, the smooth-surfaced cutting tools commonly used for soft gold or pure aluminum wires are prone to irregular relative slippage on the hard aluminum surface during crimping. To overcome this high-frequency kinetic energy dissipation problem and prevent tool breakage, such as... Figure 1 As shown, the ultrasonic chopper body 101 of this application is reinforced in its base material. Its main body is configured as a fine-grained cemented carbide or alumina-zirconia-toughened ceramic substrate, capable of withstanding the instantaneous contact compressive stress of the microscopic tip. Furthermore, a tapered amplitude amplification and variable amplitude rod region 103, gradually tapering inwards, is provided on the upper part of the outer surface of the ultrasonic chopper body 101. Through this tapered amplitude amplification and variable amplitude rod region 103, the weak high-frequency mechanical oscillations generated by the external transducer can be longitudinally amplified and focused, and transmitted to the end working area of ​​the chopper.

[0033] like Figure 2 As shown in the enlarged cross-sectional view, a central threading hole 201 for guiding the smooth transport of wire is axially provided within the working end of the ultrasonic cleaver body 101. An arc-shaped lead-in groove 202 is recessed inward on the lowest surface of the cleaver where it contacts the aluminum wire to be processed. Preferably, to conform to the cylindrical shape of the aluminum wire and provide pre-positioning in the initial stage of crimping, the geometric radius of curvature of the arc-shaped lead-in groove 202 in the radial section is set to 0.6 to 0.85 times the initial diameter of the high-hardness Al-Mg bonded aluminum wire being processed. Simultaneously, the contact surface of the lead-in groove is coated with an anti-wear coating using processes such as vacuum sputtering.

[0034] As the core structure for lossless energy downlink, this embodiment features a precise surface texture modification of the bottom surface of the arc-shaped lead groove 202, producing a micro-nano-level mesh-like rough texture. For high-strength and high-toughness Al-Mg-Sc alloys, the macroscopic depth of the micro-nano-level mesh-like rough texture is strictly limited to between 0.5 μm and 1.2 μm. In terms of microstructure, the mesh-like rough texture consists of multiple truncated pyramid-shaped protruding micro-units 204 arranged in a matrix array.

[0035] The use of a truncated pyramid shape of specific dimensions represents a balanced design that considers both penetration capability and surface contact adhesion. The top surface of each truncated pyramid-shaped protruding micro-unit 204 is cut into a flat square contact surface with a side length between 0.8 μm and 1.5 μm. The bottom of this micro-unit is a large square base surface with a side length parameter set between 2.0 μm and 3.5 μm. The four inclined sidewalls connecting the top and bottom form a design angle of 60° to 75° with the base surface, providing lateral support. To ensure uniform stress distribution, the center-to-center geometric spacing between two adjacent truncated pyramid-shaped protruding micro-units 204 is uniformly set between 3.0 μm and 5.0 μm. Through this density array arrangement, the sum of the total projected area of ​​all the flat square contact surfaces will stably occupy 35% to 55% of the total area of ​​the bottom surface of the entire arc-shaped lead slot 202.

[0036] In this array layout, adjacent truncated pyramidal protrusions 204 naturally converge to form a network of mutually orthogonal and interconnected chip removal channels 205. The bottom of this chip removal channel network 205 is not designed as a V-shaped pointed bottom, but rather as a wide, flat structure. Through this mesh-like rough texture, when the cutting tool is pressed into the hard aluminum alloy material at an ultrasonic high-frequency vibration operating frequency of 60kHz to 120kHz, the truncated flat surface design not only avoids the deep micro-crack effect in the internal alloy lattice caused by sharp angle penetration, but also relies on static friction surface contact to grasp and hold the aluminum wire surface. The chip removal channel network 205 also provides a physical channel for the discharge of extremely thin natural oxide layer debris, completely eliminating macroscopic slippage between the indenter and the high-hardness wire.

[0037] After resolving the energy coupling issue, this application addresses the problem that high-hardness aluminum alloy wires with tensile strength ≥350MPa are easily cut off directly at the cutting edge of the chopping tool due to localized high pressure. Instead of the conventional symmetrical rounded cutting edge, an asymmetrical double-chamfer structure is reconstructed in the downward-pressing area of ​​the chopping tool. This structure includes an inner chamfer 2061 and an outer chamfer 2062 from the inside out. The inner chamfer 2061 is defined at the junction of the bottom of the side wall of the central threading hole 201 and the arc-shaped lead groove 202, with a gently sloping physical chamfer angle of 45°. To eliminate the sharp edge effect, the first transition end face of the inner chamfer 2061 is smoothly connected to the straight wall of the central threading hole via a first arc surface, and its second transition end face is also smoothly connected to the lead groove area via a second arc surface. This large-angle double-arc design provides a smooth deformation transition path when the high-hardness aluminum wire is bent upwards under pressure, preventing stress cliff points. Compared to the inner side, the outer chamfer 2062 is defined between the distal outer edge of the arc-shaped lead groove 202 and the outer sidewall of the ultrasonic chopper, and its chamfer angle is set to a relatively steep 30°. This asymmetrical design can moderately increase the stress concentration effect on the outer edge during the process of lifting the pressure head to break the tail wire after welding, achieving a clean and neat cut without pulling or damaging the already welded root area inside.

[0038] Because high-hardness Al-Mg alloys are rich in L12 strengthening phases, their internal lattice deformation during ultrasonic welding, resulting in significant work hardening, causes the base material surrounding the weld joint to become brittle. This high internal pressure, which can potentially lead to cracking, is addressed by using materials such as... Figure 2 As shown, this embodiment introduces a local space clearance structure inside the chopping tool. Specifically, at the physical intersection boundary between the lowermost hole wall of the central threading hole 201 and the inner chamfer 2061 surface, a ring-shaped stress relief microcavity 207 with an inwardly concave semi-elliptical cross section is machined around the circumference.

[0039] To achieve the benefits of mechanical interlocking, the geometry of the annular stress-relieving microcavity 207 is subject to strict proportional constraints: its penetration depth into the inner wall of the wire-passing hole along the horizontal radial direction is dynamically matched according to the actual wire diameter used, specifically set to 8% to 12% of the initial diameter of the aluminum wire; simultaneously, its height extending upward along the vertical axis is set to 15% to 20% of this initial wire diameter. The inner surface of the microcavity facilitates demolding and is mirror-polished to ensure a surface roughness Ra ≤ 0.1 μm.

[0040] In actual encapsulation operations, when an ultrasonic cleaver applies a downward gravitational pressure to the Al-Mg bonded aluminum wire while simultaneously outputting lateral high-frequency ultrasonic vibration mechanical waves, specific ultrasonic energy is preferentially and selectively absorbed by the disordered dislocations within the Al-Mg alloy. This energy injection causes the dislocations to break free from their original lattice-bound positions and slide, resulting in the originally high-hardness alloy wire briefly entering a violent plastic semi-rheological state under relatively low external vertical static force.

[0041] At this instant, the rough, mesh-like texture at the bottom of the groove on the end face of the cleaver deeply engages and grips the softened aluminum alloy material at the bottom, preventing it from sliding outwards over a large area along the plane of the lower bonding substrate. The enormous plastic deformation energy, unable to dissipate to the bottom and the plane under pressure, begins to accumulate inside the aluminum wire. At this time, due to the strong physical pressure from the 30° outer chamfer 2062, the rheological material flows towards the upper hole area along the gentler slope of the 45° inner chamfer 2061, in a reverse compression manner, and then fills the pre-set annular stress-relieving microcavity 207.

[0042] After the alloy material instantly fills the microcavity space and reaches force equilibrium, it constructs a self-locking anchoring ring structure with physical support. During the subsequent ultrasonic welding maintenance phase, this anchoring ring achieves a near-rigid physical engagement between the aluminum wire matrix and the wall of the cleaver hole, providing a solid and immovable lever fulcrum for the cleaver to continue transmitting ultrasonic oscillation waves downwards. When welding is completed and the cleaver is ready to be withdrawn and lifted upwards, the annular stress-relieving microcavity 207 releases this section of anchoring ring material that has been plastically hardened and shaped, thanks to the lubrication of the polished inner surface, allowing it to remain intact directly above the bond root, ultimately manifesting as the chamfered reinforcing rib 208 structure surrounding the stress-bearing root of the lead wire. Without this upward-facing material-accommodating cavity, the enormous volumetric repulsive force generated during the downward pressing process manifests as disordered radial transverse flow of material, inevitably leading to excessive collapse of the bond point center and thinning of the root thickness, thereby inducing microcracks.

[0043] After the above-mentioned crimping operation is completed, the aluminum wire is cured on the base pad, forming the bonding structure unique to this application. The cleaving blade and parameter control of this solution can achieve high-strength bonding adaptability on the surface of various metal-clad substrates, including but not limited to silicon, copper, tin, and silver; and can improve and solve the critical intermetallic compound failure problem that is prone to occur when traditional soft aluminum wire is bonded to nickel and gold layers under high temperature environments.

[0044] Due to the controlled rheological mechanism and the anti-collapse properties of the nano-L12 reinforcing phase in the parent material, the macroscopic indentation deformation width of the bonded structure is effectively constrained and controlled, remaining stable between 1.5 and 2.2 times the original wire diameter.

[0045] Provide technical understanding support. In specific implementation, this indentation forming logic can be characterized by a deformation ratio formula that reflects the degree of deformation, and the system performs the deformation ratio calculation.

[0046] ΔW=W d / d0

[0047] In the physical quantity formula, ΔW represents the transverse deformation ratio coefficient after bonding is completed; W d d0 represents the maximum deformation width of the indentation obtained from actual measurement; d0 represents the initial nominal wire diameter of the high-hardness alloy aluminum wire before the bonding operation. Under the control of the optimal rheological constraint structure provided in this application, the calculated value of the deformation ratio ΔW does not exceed the upper limit of 2.2 times.

[0048] In terms of its microstructure, the upper surface of the indentation interface at the bonding root exhibits reverse micro-protrusions that correspond to the micro-nano mesh of the cleaver. Between the indentation interface fused by high-frequency vibration and the substrate pads, the oxide layer is violently abraded by ultrasonic energy, accompanied by the rupture and recrystallization of the underlying metal lattice, ultimately forming an extremely dense intermetallic compound bonding layer. This dense bonding layer, exhibiting a continuous wavy cross-section, directly inherits the salt spray corrosion resistance of Al-Mg special alloys, cutting off and blocking the conduction path of external corrosive substances such as free chloride ions penetrating and damaging the microstructure along the bonding interface, both physically and chemically.

[0049] A set of detailed closed-loop test data was introduced. High-strength and high-toughness Al-Mg-Sc special alloy wire with a nominal diameter of Φ25μm was selected as the test sample. A constant 30g vertical downward bonding pressure was applied on a precision motion stage, coupled with an ultrasonic drive energy of constant power 80mW. The resulting physical structure exhibited a mechanically robust morphology. Specific comparative test parameters are summarized in the following table:

[0050]

[0051] Combine with visual supplementary explanations, such as Figure 3As shown, this ultrasonic cleaver system supports an automated continuous wire bonding process. The ultrasonic pressure head module, including the motion mechanism, guides a tensioned pre-stretched aluminum wire downwards near the first solder joint (S301) through a central hole. Upon contact with the substrate, it outputs static pressure downwards and applies high-frequency ultrasonic mechanical vibrations of reciprocating friction in the horizontal direction, lasting for several milliseconds to complete the solid-state fusion of the chassis metal (S302). Subsequently, the pressure head executes a pre-planned lifting trajectory, releasing wire tension while moving towards the predetermined second solder pad target, stretching in space to form a three-dimensional parabolic lead wire arc (S303). After reaching the far end, the pressure head precisely descends again to apply heavy pressure, forming the second bonding point (S304). The actuator performs a rapid pulling action at a specific angle, utilizing the physical resistance between the cleaver edge and the formed solder joint to forcibly break off any unnecessary tail wire, achieving rapid wire breakage and returning to the starting zero position of the next wire bonding cycle (S305).

[0052] Further combining the perspective of internal component interaction, such as Figure 4 As shown, the physical connections of this action at the microscopic level can be more clearly deconstructed. The figure details the ultrasonic pressure head 401 of the peripheral system as the core pressing terminal; the Al wire 402, as the interconnecting medium, is controlled to pass through the channel. In the first impact area, the ultrasonic pressure head 401 applies a strong pressure perpendicular to the normal direction to the chip electrode 403 arranged on the bottom layer, while providing lateral high-frequency ultrasonic vibration. After being lifted and crossed by the connection, the end wire is pressed to the substrate electrode 404 on the peripheral support. After the end is formed and solidified, the excess wire at the tail is torn off by an oblique pulling action using the change of the force direction.

[0053] At the equipment system level, it is necessary to bridge the configuration with an independent ultrasonic generator and transducer assembly capable of generating stable power of 80mW or more and maintaining output in the 60kHz-120kHz frequency band; as well as a closed-loop motion servo control platform and constant wire feeding mechanism capable of precise three-dimensional spatial positioning and tracking of the cutting blade along the X-axis, Y-axis and pressing Z-axis at the micron level, to ensure the consistency of the set pressing contact force and geometric coordinates, and to ensure that the amount of material extruded into the microcavity is constant and accurate each time.

[0054] like Figure 5 As shown, after continuous operation of the aforementioned equipment and improved cutting tool, a complete semiconductor package device 501 is formed by a plurality of mutually insulated lead modules. As can be seen in the figure, the array of lead arcs 502 extending from each individual chip base is neatly arranged, with full and consistent curvature, and without obvious sagging, collapse, or root shrinkage. This high-density lead structure, manufactured using high-hardness corrosion-resistant materials and a special cutting tool, demonstrates its resilience in specialized applications, even after long-term exposure to harsh salt spray environments containing large amounts of moisture and chloride ions.

[0055] While the aforementioned detailed parameter demonstrations primarily use Φ25μm-level microfilaments as examples, based on the physical ductility of the core principle of rheological interlocking in this application, the dimensions of each key microstructure within the ultrasonic chopper can be scaled up proportionally according to a predetermined geometric amplification matrix, without any substantial deviation in its rheological control mechanism of inducing bottom-level locking and upper chamfering reinforcement. This design scheme, besides being suitable for precision microelectronic-grade packaging, is also fully backward compatible and applicable to the crimping of high-hardness macroscopic coarse aluminum wires with extremely large initial diameters. This ductility allows the implementation structure of this technical solution to be cross-domain compatible with core electronic control circuits for new energy vehicles, ultra-high-power IGBT (Insulated Gate Bipolar Transistor) semiconductor device matrices, and various high-voltage power modules, meeting the stringent requirements for redundancy in line current carrying capacity and resistance to corrosion in extreme environments under these macroscopic high-voltage application scenarios, thus expanding the commercial industrialization boundaries of this patented technology.

[0056] This embodiment proposes a solution using high-hardness materials with excellent performance but difficult processing. By specially developing an ultrasonic chopper with a mesh gripping system and a microscopic self-locking chamber collaborative clearance design, the material science challenge of easily fracturing hard materials during high-energy friction bonding is resolved without significantly increasing the burden on the manufacturing process. The introduction of self-grown metal root reinforcing ribs effectively controls the sinking deformation ratio threshold, improves the bonding strength of the pad interface and the utilization rate of ultrasonic energy introduction, and provides a new interconnect structure standard for semiconductor device packaging and testing that unifies long service life, high structural stability, and high production reliability.

[0057] The aforementioned details regarding micro-unit size ratios, specific alloy element composition parameters, and various process operating conditions are merely representative examples of the best implementation scheme of this application. Those skilled in the art, having deeply understood the core concept of the synergistic control of the anti-slip truncated mesh and the rheological energy absorption of the inner cavity material in this application, can still achieve the same goal of improving the ultrasonic crimping stability of high-hardness wires by employing equivalent mechanical displacement replacement structures or adjusting peripheral matching parameter details. Therefore, all equivalent or similar changes made within the scope of protection of this application and the content of the specification should still fall within the scope of this patent application.

Claims

1. A high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and its bonding structure, characterized in that, include: A high-hardness Al-Mg bonded aluminum wire with an initial wire diameter, the high-hardness Al-Mg bonded aluminum wire having a tensile strength greater than or equal to 350 MPa, and a Vickers hardness between 20 and 40; an ultrasonic cleaver for crimping the high-hardness Al-Mg bonded aluminum wire, the ultrasonic cleaver having a central threading hole, and an arc-shaped lead-in groove at the end of the ultrasonic cleaver, the bottom surface of the arc-shaped lead-in groove being machined with a micro-nano-level mesh-like rough texture, the depth of the micro-nano-level mesh-like rough texture being limited to between 0.5 μm and 1.2 μm; the downward pressing edge of the ultrasonic cleaver is configured with an asymmetric double-bevel structure. The asymmetric double-bevel structure includes an inner bevel and an outer bevel. The inner bevel is defined between the bottom of the central wire hole and the arc-shaped lead groove at an angle of 45°. The outer bevel is defined between the outer edge of the arc-shaped lead groove and the sidewall of the ultrasonic chopper at an angle of 30°. The high-hardness Al-Mg bonded aluminum wire is formed by being crimped by the ultrasonic chopper to form a bonding structure. The bonding structure is part of the interconnect lead module. The upper surface of the indentation interface at the bonding root of the bonding structure is distributed with reverse micro-protrusions that match the micro-nano-scale mesh-like rough texture. The indentation deformation width of the bonding structure is 1.5 to 2.2 times the initial wire diameter.

2. The high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure as described in claim 1, characterized in that, The micro-nano-scale mesh-like rough texture includes multiple truncated pyramid-shaped protruding micro-units arranged in a matrix array. An orthogonally distributed chip discharge channel network is formed between adjacent truncated pyramid-shaped protruding micro-units, and the bottom of the chip discharge channel network is a flat-bottom structure.

3. The high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure as described in claim 2, characterized in that, The top surface of each truncated pyramid-shaped protruding micro-unit is a square flat contact surface with a side length between 0.8 μm and 1.5 μm, and the bottom surface of each truncated pyramid-shaped protruding micro-unit is a square base surface with a side length between 2.0 μm and 3.5 μm; the top surface and the bottom surface are connected by four inclined sidewalls, and the inclined sidewalls form an angle of 60° to 75° with the bottom surface; the center distance between two adjacent truncated pyramid-shaped protruding micro-units is set between 3.0 μm and 5.0 μm; the total area of ​​the square flat contact surfaces accounts for 35% to 55% of the total projected area of ​​the bottom surface of the arc-shaped lead groove.

4. The high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure as described in claim 1, characterized in that, The ultrasonic chopper has an annular stress relief microcavity inside. The annular stress relief microcavity is circumferentially cut at the intersection of the lower end hole wall of the central threading hole and the inner chamfer. The annular stress relief microcavity is configured as a concave structure.

5. The high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure as described in claim 4, characterized in that, The radial penetration depth of the annular stress relief microcavity into the sidewall of the central wire hole is set to 8% to 12% of the initial wire diameter, and the axial height of the annular stress relief microcavity extending axially is set to 15% to 20% of the initial wire diameter. In the bonded state, a chamfered reinforcing rib is formed above the root of the lead wire of the bonded structure, which wraps around the high-hardness Al-Mg bonded aluminum wire. The chamfered reinforcing rib is formed by the material that enters the interior of the annular stress relief microcavity under pressure and is solidified. The outer contour of the chamfered reinforcing rib is attached to the inner wall of the annular stress relief microcavity to form a self-locking anchoring ring structure. The root thickness of the bonded structure is retained to be greater than 85% of the initial wire diameter.

6. The high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure as described in claim 1, characterized in that, The reverse micro-protrusions and the micro-nano-scale mesh-like rough texture interlock to form an interlocking interface layer, the cross-section of which has continuously arranged corrugated dense bonding bands.

7. The high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure as described in claim 1, characterized in that, The first transition end face of the inner chamfer is smoothly connected to the central wire hole through a first arc surface, and the second transition end face of the inner chamfer is smoothly connected to the arc-shaped lead groove through a second arc surface.

8. The high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure as described in claim 1, characterized in that, The main body of the ultrasonic chopper is made of fine-grained cemented carbide or alumina ceramic material, and the surface of the arc-shaped lead groove is covered with an anti-wear coating.

9. The high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and bonding structure as described in claim 1, characterized in that, The radius of curvature of the arc-shaped lead groove in the radial section is set to 0.6 to 0.85 times the initial wire diameter.

10. A semiconductor packaged device, characterized in that, It includes the high-hardness Al-Mg bonded aluminum wire ultrasonic cleaver and interconnect lead module formed by the bonding structure as described in claim 1.

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