High-density typesetting lead frame

Abstract

The utility model discloses a high-density typesetting lead frame, which relates to the technical field of electronic packaging, and comprises a conducting layer, a transition layer, a buffer layer, an insulating layer, a heat dissipation layer and a composite connection structure for connecting the layers which are stacked in sequence, and the composite connection structure comprises thermocompression bonding layers and adhesive layers which are distributed alternately. A first thermocompression bonding layer is arranged between the conductive layer and the transition layer, a second thermocompression bonding layer is arranged between the buffer layer and the insulating layer, a first cementing layer is arranged between the transition layer and the buffer layer, and a second cementing layer is arranged between the insulating layer and the heat dissipation layer. The high-density typesetting lead frame realizes integration of high-density wiring, efficient heat dissipation and high mechanical strength by cooperatively regulating thermal stress through the nano-diamond-containing silver adhesive layer and the copper alloy-aluminum oxide-molybdenum copper composite layer system and combining aluminum nitride ceramic micropore filling, the nickel-plated diamond copper heat dissipation layer and the gradient buffer strip structure design; and the reliability and the service life of the electronic device under high-temperature and high-load working conditions are remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of electronic packaging technology, specifically a high-density layout lead frame. Background Technology

[0002] As electronic devices develop towards high-density integration and high power, traditional lead frames face severe challenges under complex operating conditions.

[0003] In existing technologies, lead frames often employ a single material or a simple layered structure, resulting in significant mismatches in the coefficient of thermal expansion (CTE) between layers. This leads to stress concentration at the interface under temperature cycling, easily causing interlayer delamination or microcrack propagation, severely impacting long-term reliability. For example, if the conductive and insulating layers are directly bonded using ordinary adhesives, the poor thermal conductivity and insufficient thermal stability of the adhesive layer make it prone to aging and failure at high temperatures, exacerbating the increase in thermal resistance. Conversely, insufficient thermal conductivity or poor interfacial bonding of the heat dissipation layer material makes it difficult to meet the heat dissipation requirements of high-power devices, leading to excessively high local temperature rises. Furthermore, existing interlayer connections often employ single adhesive bonding or thermocompression bonding. Adhesive bonding interfaces are prone to fatigue damage due to sudden stress changes, while thermocompression bonding areas may experience brittle fracture due to differences in material rigidity. Regarding insulating layer design, the interface contact area between conventional ceramic substrates and metal layers is limited, resulting in insufficient bonding strength and a lack of active stress buffering mechanisms, making it difficult to withstand the mechanical loads brought about by high-density wiring.

[0004] Therefore, in order to address the above problems, the applicant needs to design a high-density typesetting leader frame to solve the problem. Utility Model Content

[0005] The purpose of this invention is to provide a high-density typesetting lead frame to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a high-density typesetting lead frame, comprising a conductive layer, a transition layer, a buffer layer, an insulating layer, a heat dissipation layer, and a composite connection structure for connecting the layers in sequence. The composite connection structure includes alternating hot-press bonding layers and adhesive layers. A first hot-press bonding layer is disposed between the inner side of the conductive layer and the outer side of the transition layer. A second hot-press bonding layer is disposed between the inner side of the buffer layer and the outer side of the insulating layer. A first adhesive layer is disposed between the inner side of the transition layer and the outer side of the buffer layer. A second adhesive layer is disposed between the inner side of the insulating layer and the outer side of the heat dissipation layer.

[0007] Furthermore, both the first adhesive layer and the second adhesive layer are silver epoxy adhesives containing nanodiamonds.

[0008] Through the above structural design, by using silver epoxy adhesive containing nanodiamonds as the first and second adhesive layers, the thermal conductivity and electrical conductivity of the adhesive interface are significantly improved.

[0009] Furthermore, the conductive layer is a copper alloy, the transition layer is a copper / alumina metal-based composite material, and the buffer layer is a molybdenum-copper alloy.

[0010] Through the above structural design, the copper alloy conductive layer provides high conductivity and cost advantages, while the copper / alumina composite transition layer effectively alleviates the thermal stress mismatch problem between the conductive layer and the subsequent layers by adjusting the difference in thermal expansion coefficients.

[0011] Furthermore, the insulating layer is an aluminum nitride ceramic copper-clad laminate, and the surface of the aluminum nitride ceramic substrate is provided with a micropore array, which is filled with a tin-bismuth eutectic alloy.

[0012] Through the above structural design, the aluminum nitride ceramic copper-clad laminate has both high insulation and thermal conductivity. The microporous array increases the interlayer bonding force by increasing the contact area, and the tin-bismuth eutectic alloy filler utilizes its low melting point characteristics to flow and fill the interface gaps at high temperatures, thereby enhancing heat transfer efficiency and buffering local stress.

[0013] Furthermore, the heat dissipation layer is nickel-plated diamond copper.

[0014] Through the above structural design, the nickel-plated diamond copper heat dissipation layer achieves rapid heat dissipation by utilizing the high thermal conductivity of diamond and the excellent thermal diffusion capability of copper.

[0015] Furthermore, a gradient buffer zone is provided at the junction of the first adhesive layer, the first hot-pressed bonding layer, the second adhesive layer, and the second hot-pressed bonding layer. The adhesive content of the gradient buffer zone decreases from 100% to 0%, while the hot-pressed bonding area increases from 0% to 100%.

[0016] Through the above structural design, the gradient buffer band achieves a smooth transition between the adhesive layer and the hot-pressed bonding layer by continuously varying the adhesive content and the hot-pressing area, eliminating stress abrupt changes at the interface, thereby ensuring the structural stability of the lead frame under complex working conditions.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] This high-density wiring leadframe achieves comprehensive performance enhancement through material optimization and structural innovation: the silver epoxy adhesive layer containing nanodiamonds enhances mechanical stability while ensuring high electrical and thermal conductivity; the copper alloy conductive layer, copper / alumina transition layer, and molybdenum-copper buffer layer synergistically reduce the difference in thermal expansion coefficients, effectively alleviating thermal stress; the microporous array of aluminum nitride ceramic copper-clad laminate and the tin-bismuth alloy filling optimize the thermal conductivity of the insulation layer and the interfacial bonding strength; the nickel-plated diamond copper heat dissipation layer, combined with high thermal conductivity materials and anti-oxidation coating, significantly improves heat dissipation efficiency; the gradient buffer strip eliminates interfacial stress concentration through a smooth transition between adhesive bonding and hot pressing, ensuring the reliability and fatigue resistance of interlayer connections. The overall structure takes into account high-density wiring, thermal management, mechanical strength, and long-term stability, making it suitable for harsh operating conditions such as high temperature and high current, and extending the service life of electronic devices. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall three-dimensional structure of this utility model;

[0020] Figure 2 This is a schematic diagram of the overall disassembled structure of this utility model;

[0021] Figure 3 This is a schematic diagram of the layered structure of this utility model.

[0022] In the figure: 1. Conductive layer; 2. Transition layer; 3. Buffer layer; 4. Insulating layer; 5. Heat dissipation layer; 6. First adhesive layer; 7. Second adhesive layer; 8. Hot-press bonding layer one; 9. Hot-press bonding layer two. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] like Figures 1-3 As shown, a high-density typesetting lead frame of this utility model includes a conductive layer 1, a transition layer 2, a buffer layer 3, an insulating layer 4, a heat dissipation layer 5, and a composite connection structure for connecting the layers in sequence. The composite connection structure includes alternating hot-press bonding layers and adhesive layers. A first hot-press bonding layer 8 is provided between the inner side of the conductive layer 1 and the outer side of the transition layer 2. A second hot-press bonding layer 9 is provided between the inner side of the buffer layer 3 and the outer side of the insulating layer 4. A first adhesive layer 6 is provided between the inner side of the transition layer 2 and the outer side of the buffer layer 3. A second adhesive layer 7 is provided between the inner side of the insulating layer 4 and the outer side of the heat dissipation layer 5.

[0025] Both the first adhesive layer 6 and the second adhesive layer 7 are silver epoxy adhesives containing nanodiamonds. By using silver epoxy adhesives containing nanodiamonds as the first adhesive layer 6 and the second adhesive layer 7, the thermal conductivity and electrical conductivity of the adhesive interface are significantly improved. The addition of nanodiamonds enhances the mechanical strength and wear resistance of the adhesive layer. At the same time, the silver-based material ensures excellent electrical connection performance, thereby maintaining stable interlayer bonding under high temperature and high current conditions, reducing the risk of adhesive layer aging or cracking caused by thermal cycling, and extending the service life of the lead frame.

[0026] The conductive layer 1 is a copper alloy, the transition layer 2 is a copper / alumina metal matrix composite material, and the buffer layer 3 is a molybdenum-copper alloy. The copper alloy conductive layer 1 provides high conductivity and cost advantages. The copper / alumina composite transition layer effectively alleviates the thermal stress mismatch problem between the conductive layer 1 and the subsequent layers by adjusting the difference in thermal expansion coefficients. The molybdenum-copper alloy buffer layer 3, with its moderate thermal expansion coefficient and elastic modulus, further absorbs and disperses thermomechanical stress, preventing microcracks from forming between layers due to temperature fluctuations, thereby improving the reliability of the overall structure.

[0027] The insulating layer 4 is an aluminum nitride ceramic copper-clad laminate, and the surface of the aluminum nitride ceramic substrate is provided with a micropore array. The micropore array is filled with a tin-bismuth eutectic alloy. The aluminum nitride ceramic copper-clad laminate has both high insulation and thermal conductivity. The micropore array increases the interlayer bonding force by increasing the contact area. The tin-bismuth eutectic alloy filler utilizes its low melting point characteristics to flow and fill the interface gaps at high temperatures, enhancing heat transfer efficiency and buffering local stress, further optimizing the thermal matching and interface integrity between the insulating layer 4 and the adjacent layers.

[0028] The heat dissipation layer 5 is nickel-plated diamond copper. The nickel-plated diamond copper heat dissipation layer 5 achieves rapid heat dissipation by utilizing the high thermal conductivity of diamond and the excellent thermal diffusion ability of copper. The nickel plating layer not only prevents the copper substrate from oxidizing, but also strengthens the interface bonding strength with the insulating layer 4, ensuring the long-term stable and efficient operation of the heat dissipation channel and significantly reducing the impact of high temperature on the performance of core electronic components.

[0029] A gradient buffer zone is provided at the junction of the first adhesive layer 6, the first hot-pressed bonding layer 8, the second adhesive layer 7, and the second hot-pressed bonding layer 9. The adhesive content of the gradient buffer zone decreases from 100% to 0%, while the hot-pressed bonding area increases from 0% to 100%. Through the continuous gradient change of adhesive content and hot-pressed area, the gradient buffer zone achieves a smooth transition between the adhesive layer and the hot-pressed bonding layer, eliminates stress abrupt changes at the interface, avoids local peeling or crack propagation caused by differences in connection methods, significantly improves the consistency of interlayer bonding and fatigue resistance, and ensures the structural stability of the lead frame under complex working conditions.

[0030] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A high-density typesetting lead frame, characterized in that: The system includes a conductive layer (1), a transition layer (2), a buffer layer (3), an insulating layer (4), a heat dissipation layer (5) stacked sequentially, and a composite connection structure for connecting the layers. The composite connection structure includes alternating hot-press bonding layers and adhesive layers. A first hot-press bonding layer (8) is provided between the inner side of the conductive layer (1) and the outer side of the transition layer (2). A second hot-press bonding layer (9) is provided between the inner side of the buffer layer (3) and the outer side of the insulating layer (4). A first adhesive layer (6) is provided between the inner side of the transition layer (2) and the outer side of the buffer layer (3). A second adhesive layer (7) is provided between the inner side of the insulating layer (4) and the outer side of the heat dissipation layer (5).

2. The high-density typesetting lead frame according to claim 1, characterized in that: Both the first adhesive layer (6) and the second adhesive layer (7) are silver epoxy adhesives containing nanodiamonds.

3. A high-density typesetting lead frame according to claim 1, characterized in that: The conductive layer (1) is a copper alloy, the transition layer (2) is a copper / alumina metal matrix composite material, and the buffer layer (3) is a molybdenum copper alloy.

4. A high-density typesetting lead frame according to claim 1, characterized in that: The insulating layer (4) is an aluminum nitride ceramic copper-clad laminate, and the surface of the aluminum nitride ceramic substrate is provided with a micropore array, which is filled with a tin-bismuth eutectic alloy.

5. A high-density typesetting lead frame according to claim 1, characterized in that: The heat dissipation layer (5) is nickel-plated diamond copper.

6. A high-density typesetting lead frame according to claim 1, characterized in that: A gradient buffer zone is provided at the junction of the first adhesive layer (6), the first hot-pressed bonding layer (8), the second adhesive layer (7) and the second hot-pressed bonding layer (9). The adhesive content of the gradient buffer zone decreases from 100% to 0%, while the hot-pressed bonding area increases from 0% to 100%.

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