TO252 type thick material high-integration lead frame
The TO252 thick-material high-integration leadframe with a dual-layer design solves the problem of insufficient heat dissipation performance of traditional leadframes in high-current applications, achieving high-density packaging and stability, and is suitable for the high integration requirements of power devices.
Patent Information
- Application Number
- CN202423166604.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-12-30
- Estimated Expiration
- 2034-12-20
AI Technical Summary
Traditional TO-252 lead frames have insufficient heat dissipation performance in high-current applications, which cannot effectively handle heat, resulting in temperature rise that affects device life and stability. At the same time, it is difficult to achieve high-density component arrangement in multi-chip modules or multi-layer circuit boards, and the production is complex and costly.
The TO252 thick-material high-integration lead frame adopts a double-layer design structure. By arranging multiple rows of lead frame groups at intervals in the upper and lower parts of the frame body and connecting adjacent components with transverse ribs, and combining the first and second types of lead frame modules, a stable three-point support structure and a reliable heat conduction channel are formed, which improves space utilization and heat dissipation efficiency.
It significantly improves heat dissipation performance and integration, simplifies manufacturing processes, ensures electrical characteristics and reliability, and is suitable for high-current, multi-pin power device applications.
Smart Images
Figure CN223743663U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a lead frame, especially a TO252 type thick material high integration lead frame. BACKGROUND
[0002] TO-252 (also known as DPAK) type packaging is a widely used miniaturized surface mount device (SMD) packaging form in power electronic components, which is particularly common in power transistors, diodes and other discrete semiconductor devices, and is favored for its ability to provide good heat dissipation performance and electrical characteristics. However, as electronic devices move towards smaller and more efficient directions, traditional TO-252 lead frames face challenges in meeting these new requirements.
[0003] Traditional designs often focus on the optimization of individual components, ignoring the possibility of system-level integration, which not only limits the overall performance improvement, but also increases manufacturing costs and complexity. In addition, existing TO-252 lead frames are mainly composed of metal materials, usually copper alloy or iron-nickel alloy, with a certain thickness to ensure sufficient mechanical strength and electrical conductivity. However, when it comes to high-current applications, traditional materials and structures may not be able to effectively handle the generated heat, leading to temperature rise affecting device life and stability. In addition, the design of traditional frames is insufficient to support multi-chip modules or multi-layer circuit boards, making it difficult to achieve higher density of component arrangement.
[0004] To address these issues, the market urgently needs a new thick material high integration lead frame that can further enhance integration, reduce thermal resistance and simplify production processes while maintaining or improving existing advantages. SUMMARY
[0005] The purpose of the utility model is to provide a TO252 type thick material high integration lead frame, which can significantly improve heat dissipation performance, increase integration and simplify manufacturing processes, while ensuring excellent electrical characteristics and reliability.
[0006] To achieve the above purpose, the utility model provides the following technical scheme: a TO252 type thick material high integration lead frame, comprising a frame body and a plurality of rows of lead frame groups, the lead frame groups are fixedly arranged in the frame body with an interval between the upper and lower rows, and the adjacent lead frame groups are connected by transverse ribs, the lead frame group comprises first type lead frame modules arranged on the front side and the rear side, and second type lead frame modules arranged in the middle, wherein:
[0007] The first type of lead frame module comprises a plurality of first type of lead frame units arranged left and right, each of the first type of lead frame units comprising a first base island, a first pin and a second pin, one end of the first base island being connected to the frame body through a first heat sink, the other end of the first base island being connected to the transverse rib through a first bent leg, the first pin and the second pin being arranged left and right on the corresponding transverse rib;
[0008] The second type of lead frame module comprises a plurality of second type of lead frame units arranged left and right, each of the second type of lead frame units comprising a second base island, a third base island, a third pin, a fourth pin, a fifth pin and a sixth pin, the second base island and the third base island being arranged front and back, the second base island being connected to a second heat sink, the third base island being connected to a third heat sink, the second heat sink being connected to the third heat sink through a longitudinal connecting rib, the second base island being further connected to the front transverse rib through a second bent leg, the third base island being further connected to the rear transverse rib through a third bent leg, the third pin and the fourth pin being arranged left and right on the front transverse rib, the fifth pin and the sixth pin being arranged left and right on the rear transverse rib.
[0009] Preferably, the frame body comprises a front frame and a rear frame arranged front and back, a plurality of circular or elliptical positioning holes being formed on the front frame and the rear frame respectively.
[0010] Preferably, at least one cut leg is connected between the front frame and the corresponding first heat sink, and between the rear frame and the corresponding first heat sink.
[0011] Preferably, the first base island, the second base island and the third base island are located below the transverse rib, and the height difference between the first base island, the second base island and the third base island and the transverse rib is 1.05-1.09mm.
[0012] Preferably, the first pin, the second pin, the third pin, the fourth pin, the fifth pin and the sixth pin are respectively provided with a soldering area, and the surface of the soldering area is coated with a silver plating layer.
[0013] Preferably, the first bent leg, the second bent leg and the third bent leg have the same structure size, comprising a first connecting segment, an inclined segment and a second connecting segment connected to each other, wherein the first connecting segment is fixedly connected to the corresponding base island, and the inclined segment has an inclination angle of 45-70 degrees with the horizontal plane.
[0014] Compared with the prior art, the lead frame has the advantages that: the lead frame adopts an innovative double-layer design structure, a plurality of lead frame groups are arranged in the frame body in an up-down interval mode, and adjacent groups are connected by a horizontal rib, so that the space utilization is remarkably improved.The core is that a first type lead frame module on the front side and the rear side is combined with a second type lead frame module in the middle part, the first type lead frame module adopts a single base island design, is connected with the frame body through a first heat dissipation fin, and is connected with the horizontal rib through a first bending foot, so that a stable three-point support structure is formed, the mechanical stability of the element is ensured, and the second type lead frame module adopts a double-base island arrangement design, not only forms a reliable heat conduction channel through a second heat dissipation fin and a third heat dissipation fin, but also connects the two heat dissipation fins through a longitudinal connecting rib, so that a larger heat dissipation area is formed, the heat dissipation efficiency is effectively improved, through the layout mode, more devices can be accommodated in the same space, while the stability of the structure and the reliability of the welding process are ensured, the design not only realizes high-density packaging, but also considers the heat dissipation performance and the structural strength, and is particularly suitable for a power device application scene that needs large current and multiple pin connections. BRIEF DESCRIPTION OF DRAWINGS
[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by the drawings provided by the person skilled in the art without creative labor.
[0016] Figure 1 is a structural schematic view of the present application;
[0017] Figure 2 is a structural schematic view of the present application
[0018] Figure 3 is a structural schematic view of the first type lead frame module in the present application;
[0019] Figure 4 is a structural schematic view of the present application Figure 3 is a sectional view of B-B in the present application;
[0020] In the figure: 1, frame body; 2, lead frame group; 3, transverse rib; 4, first type lead frame module; 5, second type lead frame module; 6, first type lead frame unit; 7, first base island; 8, first pin; 9, second pin; 10, first fin; 11, first bent leg; 12, second type lead frame unit; 13, second base island; 14, third base island; 15, third pin; 16, fourth pin; 17, fifth pin; 18, sixth pin; 19, second fin; 20, third fin; 21, longitudinal connecting rib; 22, second bent leg; 23, third bent leg; 24, front frame; 25, rear frame; 26, positioning hole; 27, cut leg; 28, silver plating layer; 29, first connecting section; 30, inclined section; 31, second connecting section. DETAILED DESCRIPTION
[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.
[0022] Embodiment one: as shown in the figure, a TO252 type thick material high integration lead frame, comprising a frame body 1 and a plurality of rows of lead frame groups 2, the plurality of rows of lead frame groups 2 are fixedly arranged in the frame body 1 with an interval up and down, and the adjacent lead frame groups 2 are connected through the transverse ribs 3, the lead frame group 2 comprises the first type lead frame module 4 arranged on the front side and the rear side and the second type lead frame module 5 arranged in the middle, wherein:
[0023] The first type lead frame module 4 comprises a plurality of first type lead frame units 6 arranged with an interval left and right, each type lead frame unit comprises a first base island 7, a first pin 8 and a second pin 9, one end of the first base island 7 is connected with the frame body 1 through the first fin 10, the other end of the first base island 7 is connected with the transverse rib 3 through the first bent leg 11, and the first pin 8 and the second pin 9 are arranged with an interval left and right on the corresponding transverse rib 3;
[0024] The second type of lead frame module 5 comprises a plurality of second type of lead frame units 12 arranged left and right, each of which comprises a second base island 13, a third base island 14, a third pin 15, a fourth pin 16, a fifth pin 17 and a sixth pin 18, the second base island 13 and the third base island 14 are arranged front and back, and the second base island 13 is connected with a second heat sink 19, the third base island 14 is connected with a third heat sink 20, the second heat sink 19 is connected with the third heat sink 20 through a longitudinal connecting rib 21, the second base island 13 is further connected with the front transverse rib 3 through a second bending leg 22, the third base island 14 is further connected with the rear transverse rib 3 through a third bending leg 23, the third pin 15 and the fourth pin 16 are arranged left and right on the front transverse rib 3, and the fifth pin 17 and the sixth pin 18 are arranged left and right on the rear transverse rib 3.
[0025] Embodiment two: as shown in the figure, different from embodiment one, the frame body 1 comprises a front frame 24 and a rear frame 25 arranged front and back, and a plurality of circular or elliptical positioning holes 26 are arranged on the front frame 24 and the rear frame 25 respectively.
[0026] The design of the front and rear frames 25 enhances the structural strength of the overall frame and provides stable support for the lead frame group 2, and the arrangement of the circular or elliptical positioning holes 26 plays an important role in the production process. These positioning holes 26 can be used as reference points for accurate positioning, ensuring that the lead frame can be accurately aligned during the processes of conveying, assembling and packaging, thereby improving the accuracy and consistency of product manufacturing.
[0027] In this embodiment, at least one cutting leg 27 is connected between the front frame 24 and the corresponding first heat sink 10 and between the rear frame 25 and the corresponding first heat sink 10.
[0028] The pre-set cutting leg 27 position can achieve accurate cutting of the frame, avoiding damage or deformation of the heat sink and base island during the separation process. The design of the cutting leg 27 structure also takes into account the need for stress dispersion. By arranging the cutting leg 27 at both ends, the stress generated during the die cutting and separation of the frame can be effectively dispersed, preventing deformation or cracking of the frame caused by stress concentration. It is worth noting that the number of cutting legs 27 can be flexibly adjusted according to actual needs.
[0029] In this embodiment, the first base island 7, the second base island 13 and the third base island 14 are located below the transverse rib 3, and the height difference between the first base island 7, the second base island 13 and the third base island 14 and the transverse rib 3 is 1.05-1.09mm.
[0030] In the above structure, the base island adopts a sunken layout, and the first base island 7, the second base island 13 and the third base island 14 are arranged below the transverse rib 3, and the height difference is strictly controlled within the range of 1.05-1.09 mm. This design has significant value in practical application. The sunken layout provides a stable mounting platform for the chip, enabling the chip to be firmly fixed on the surface of the base island and effectively preventing the chip from shifting in the subsequent process. The height difference of 1.05-1.09 mm not only ensures the overall balance of the lead frame, but also provides a good working space for the subsequent bonding process, facilitating the arrangement and fixation of the solder wire.
[0031] This structural design also fully considers the mold sealing requirement in the packaging process. Through reasonable height difference matching, it can effectively prevent the overflow of plastic sealing material, improve the sealing performance and reliability of the product, and also improve the yield rate in the production process.
[0032] In example three, as shown in the figure, the first pin 8, the second pin 9, the third pin 15, the fourth pin 16, the fifth pin 17 and the sixth pin 18 are respectively provided with a soldering area, and the surface of the soldering area is coated with a silver plating layer 28.
[0033] The first pin 8, the second pin 9, the third pin 15, the fourth pin 16, the fifth pin 17 and the sixth pin 18 are respectively provided with a soldering area, and the surface of the soldering area is coated with a silver plating layer 28 with good conductivity and oxidation resistance. On the one hand, it can improve the reliability and service life of the pin and the external circuit soldering connection. On the other hand, the specially designed soldering area is also conducive to the accurate arrangement of the solder in the specified area, avoiding the risk of short circuit caused by accidental spread of solder, and facilitating the automation of subsequent assembly process, improving production efficiency and consistency.
[0034] In this embodiment, the first bending leg 11, the second bending leg 22 and the third bending leg 23 have the same structure size, which includes a first connecting segment 29, an inclined segment 30 and a second connecting segment 31 connected to each other. The first connecting segment 29 is fixedly connected to the corresponding base island, and the inclined segment 30 has an inclination angle of 45-70 degrees with the horizontal plane.
[0035] This bending structure can increase the connection strength between the lead frame and the base island, and improve the overall structural stability. On the other hand, the inclined segment 30 can act as a buffer to reduce the thermal expansion and contraction stress between the base islands and the transverse rib 3 under temperature changes and other working conditions. Designing the bending legs with uniform structure size is conducive to standardized production and improves manufacturing efficiency. The reasonable inclination angle of 45-70 degrees can ensure sufficient stress buffer space while avoiding excessive occupation of horizontal space.
[0036] The above merely describes the embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, which is made by using the content of the present application specification and drawings, is also included in the patent protection scope of the present application.
Claims
1. A TO252 type thick material high integration lead frame, comprising a frame body and a plurality of rows of lead frame groups, the plurality of rows of lead frame groups are fixedly arranged in the frame body in an up-down interval, and the adjacent lead frame groups are connected by a transverse rib, characterized in that: The lead frame group comprises first type lead frame modules arranged at the front side and the rear side and second type lead frame modules arranged at the middle part, wherein: The first type lead frame module comprises a plurality of first type lead frame units arranged at intervals left and right, each of the first type lead frame units comprising a first base island, a first pin and a second pin, one end of the first base island being connected with the frame body through a first heat dissipation fin, the other end of the first base island being connected with the transverse rib through a first bent leg, the first pin and the second pin being arranged at intervals left and right on the corresponding transverse rib; The second type lead frame module comprises a plurality of second type lead frame units arranged at intervals left and right, each of the second type lead frame units comprising a second base island, a third base island, a third pin, a fourth pin, a fifth pin and a sixth pin, the second base island and the third base island being distributed at intervals front and back, the second base island being connected with a second heat dissipation fin, the third base island being connected with a third heat dissipation fin, the second heat dissipation fin being connected with the third heat dissipation fin through a longitudinal connecting rib, the second base island being further connected with the transverse rib at the front side through a second bent leg, the third base island being further connected with the transverse rib at the rear side through a third bent leg, the third pin and the fourth pin being arranged at intervals left and right on the transverse rib at the front side, the fifth pin and the sixth pin being arranged at intervals left and right on the transverse rib at the rear side.
2. The TO252 type thick material high integration lead frame according to claim 1, wherein: The frame body comprises a front frame and a rear frame distributed front and back, a plurality of circular or elliptical positioning holes being formed on the front frame and the rear frame respectively.
3. The TO252 type thick material high integration lead frame according to claim 2, characterized in that: At least one cut leg is connected between the front frame and the corresponding first heat dissipation fin and between the rear frame and the corresponding first heat dissipation fin.
4. The TO252 type thick material high integration lead frame according to claim 1, wherein: The first base island, the second base island and the third base island are located below the transverse rib, and the height difference between the first base island, the second base island and the third base island and the transverse rib is 1.05-1.09 mm.
5. The TO252 type thick material high integration lead frame according to claim 1, wherein: A welding area is arranged on each of the first pin, the second pin, the third pin, the fourth pin, the fifth pin and the sixth pin, and a silver plating layer is coated on the surface of the welding area.
6. The TO252 type thick material high integration lead frame according to claim 1, wherein: The first bent leg, the second bent leg and the third bent leg have the same structure size, comprising a first connecting section, an inclined section and a second connecting section connected with each other, wherein the first connecting section is fixedly connected with the corresponding base island, and the inclined section has an inclination angle of 45-70 degrees with the horizontal plane.