A new lead frame

Abstract

The utility model discloses a novel lead frame belongs to the technical field of semiconductor packaging. It includes a pair of parallel frame, and is equipped with at least one group of lead frame unit group between the frame, and the unit group contains four 2x2 matrix arrangement's frame unit, and is equipped with the central connecting area in the center. The frame unit is divided into left and right half, and each contains the slide area and the pin area, and the slide area is equipped with V-shaped groove and the flange abutment, and is connected with the top pin through the slide extension area, and the extension area has the lock glue groove and the dovetail groove. The central connecting area is triangular, and is equipped with the flow guide hole, and is connected with the bottom pin connection middle rib and horizontal rib. The utility model strengthens the structure rigidity, and optimizes the package consistency and the heat dissipation stability, and perfects the mistake proof system, and promotes the connection reliability, and is applicable to the top heat dissipation power device package.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor packaging technology, specifically to a novel lead frame. Background Technology

[0002] Leadframes are critical components in semiconductor packaging, used to carry the chip, enable electrical connections between the chip and external circuits, and provide structural support for the device. Power devices generate a large amount of heat during operation, and good heat dissipation performance is crucial to ensuring their power density and lifespan. Top-heat dissipation technology is widely used because it can directly and quickly dissipate heat through the substrate area.

[0003] Existing technologies for top-heat-dissipating power devices suffer from several drawbacks in their lead frames: First, the structural design is flawed, with improper height differences between the carrier area and the lead area, obstructing heat conduction paths and resulting in low heat dissipation efficiency. Second, in the packaging process, the long flow channel design of the single-injection head mold leads to uneven filling of the molding compound, affecting not only packaging quality but also causing inconsistent heat dissipation performance due to variations in the distribution of packaging materials. Third, the simple surface structure of the carrier area results in insufficient adhesion to the packaging material, making it prone to gaps that affect heat conduction. Furthermore, the lack of effective limiting structures means that chip misalignment can lead to misalignment of the heat dissipation path. These problems severely restrict the application of top-heat-dissipating technology in power devices, thus necessitating the design of a novel lead frame that optimizes the heat dissipation path and improves packaging consistency. Utility Model Content

[0004] The purpose of this invention is to provide a novel lead frame to solve the problems of low packaging efficiency, poor structural stability and insufficient heat dissipation performance at the top in the prior art.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution: a novel lead frame, comprising a pair of parallel side frames, at least one set of lead frame unit groups between the side frames, the lead frame unit group comprising multiple frame units arranged in an array, each frame unit comprising a substrate area and a pin area, the pin area being connected to the side frames through a connecting structure, and a central connecting area connected to each frame unit being provided in the middle of the lead frame unit group.

[0006] As a further improvement to the technical solution of this utility model, the lead frame unit group includes four frame units, which are arranged in a 2×2 matrix, and the central connection area is provided at the geometric center of the four frame units.

[0007] As a further improvement to the technical solution of this utility model, the pin area includes top pins and bottom pins, which are located on both sides of the substrate area, and the central connection area is connected to the top pins of each frame unit.

[0008] As a further improvement to the technical solution of this utility model, the frame unit is divided into an upper part and a lower part. In the two frame units of the upper part, the upper side of the substrate area is the top pin and the lower side is the bottom pin; in the two frame units of the lower part, the lower side of the substrate area is the bottom pin and the upper side is the top pin.

[0009] As a further improvement to the technical solution of this utility model, a first vertical rib and a second vertical rib are respectively provided between the two frame units in the upper part and the two frame units in the lower part.

[0010] As a further improvement to the technical solution of this utility model, the bottom pin includes at least two pin bodies arranged in parallel, and the pin bodies are connected by a connecting rib.

[0011] As a further improvement to the technical solution of this utility model, the central connecting area is a polygonal structure with several through-holes on its surface, and the through-holes extend along the central connecting area in the direction of each frame unit.

[0012] As a further improvement to the technical solution of this utility model, the substrate area is a rectangular structure with a V-shaped groove on its edge, and the three sides of the substrate area away from the pin area are provided with flanged supports.

[0013] As a further improvement to the technical solution of this utility model, the frame is provided with spaced positioning holes, including circular positioning holes and elliptical positioning holes, and one side of the frame is also provided with anti-reverse holes.

[0014] As a further improvement to the technical solution of this utility model, the substrate area and the top pin are connected by a substrate extension area, and the substrate extension area is provided with an elliptical locking groove and a dovetail groove.

[0015] This utility model has the following beneficial effects:

[0016] Optimize the top heat dissipation path: By setting the plane of the carrier area and the top pins to a sunken structure lower than the bottom pins, the back of the carrier area can be directly exposed to the external environment, and heat can be directly dissipated through the metal carrier area, reducing thermal resistance; at the same time, the tight fit between the carrier area and the chip and the limiting effect of the flanged platform ensure the stability of the heat dissipation path, solving the problem of blocked heat dissipation path in the prior art.

[0017] Improved packaging consistency and heat dissipation stability: The design of the central connection area and the flow guide hole allows the molding compound to flow evenly from the center to all frame units. Combined with the short flow channel design of the multi-injection head mold, it avoids the problem of uneven filling caused by the long flow channel of a single injection head, ensuring that the packaging material distribution of each frame unit is consistent, thereby ensuring the consistency of heat dissipation performance and reducing heat dissipation fluctuations caused by packaging differences.

[0018] Enhanced structural bonding and thermal conductivity: The V-shaped groove in the substrate area, the elliptical locking groove and dovetail groove in the substrate extension area significantly improve the mechanical bonding strength between the molding compound and the lead frame, preventing interface separation during high-temperature operation and ensuring that heat can be efficiently conducted through the close contact between the encapsulation material and the substrate area, solving the problem of increased thermal resistance caused by insufficient bonding strength in the prior art.

[0019] Improved material utilization and process adaptability: The use of 0.5mm copper strip of the same profile for stamping reduces the requirements for material selection and processing compared to profiles, saving raw material costs; at the same time, the design of at least 6 sets of lead frame units arranged in parallel, combined with the central distribution structure, can be adapted to standard multi-injection head molding molds, encapsulating more products at once, improving production efficiency, and the setting of positioning holes and anti-reverse holes ensures processing accuracy and guarantees structural consistency during mass production.

[0020] Enhancing structural stability and reliability: The design of the first vertical rib, the second vertical rib, and the connecting central rib enhances the overall rigidity of the frame unit group, reduces deformation during stamping and packaging, and ensures the relative positional accuracy of the wafer area and the pin area; the spacing layout of the bottom pins and the rectangular design of the wafer area provide a stable bearing space for the chip while ensuring electrical isolation, reducing the risk of heat dissipation failure caused by structural deformation. Attached Figure Description

[0021] Other features, objects, and advantages of this invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0022] Figure 1 is one of the overall structural schematic diagrams of the lead frame unit group according to an embodiment of the present utility model;

[0023] Figure 2 is one of the overall structural schematic diagrams of the frame unit in an embodiment of this utility model;

[0024] Figure 3 is a front view of a novel lead frame according to an embodiment of the present invention;

[0025] Figure 4 is one of the side views of a novel lead frame according to an embodiment of the present invention;

[0026] Figure 5 is a second side view of a novel lead frame according to an embodiment of the present invention;

[0027] Figure 6 is a second schematic diagram of the overall structure of the lead frame unit group according to an embodiment of the present invention;

[0028] Figure 7 This is the second schematic diagram of the overall structure of the frame unit in an embodiment of this utility model;

[0029] Figure 8 is a schematic diagram of a packaged sample of a novel lead frame according to an embodiment of the present invention.

[0030] In the attached diagram: 1-First frame, 2-Second frame, 3-Leader frame unit group, 4-Frame unit, 5-Carrier area, 6-Top pin, 7-Bottom pin, 8-Central connection area, 9-First vertical rib, 10-Second vertical rib, 11-Connecting central rib, 12-Guide hole, 13-V-groove, 14-Flanged support, 15-Positioning hole, 16-Anti-reverse hole, 17-Carrier extension area, 18-Fixing groove, 19-Dovetail groove; 100-Leader frame. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0032] It should be noted that all directional indicators (such as up, down, left, right, front, back, upper end, lower end, top, bottom, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0033] In this utility model, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0034] Furthermore, in this utility model, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination should be considered non-existent and not within the scope of protection claimed by this utility model.

[0035] The present invention will be further described in detail below with reference to the accompanying drawings.

[0036] Refer to Figure 1 to Figure 8A novel lead frame 100 includes a pair of parallel side frames, each side frame including a first side frame 1 and a second side frame 2; at least one set of lead frame unit groups 3 is provided between the side frames, each lead frame unit group 3 includes a plurality of frame units 4 arranged in an array, each frame unit 4 includes a substrate area 5 and a pin area, the pin area is connected to the side frame by a connection structure, and a central connection area 8 is provided in the middle of the lead frame unit group 3, which is connected to each frame unit 4.

[0037] Specifically, in this embodiment, the lead frame unit group 3 includes four frame units 4 arranged in a 2×2 matrix, and the central connection area 8 is located at the geometric center of the four frame units 4. This layout allows the molding compound to flow evenly from the center to the periphery, improving encapsulation consistency, while ensuring consistent heat dissipation conditions in the carrier area 5 of each frame unit 4.

[0038] Specifically, in this embodiment, the pin area includes a top pin 6 and a bottom pin 7, which are located on opposite sides of the substrate area 5. The central connection area 8 is connected to the bottom pin 7 of each frame unit 4. It should be noted that connecting the central connection area 8 to the top pin 7 enhances the overall structural strength and provides guidance for the flow of molding compound, while avoiding obstruction of the heat dissipation path of the substrate area 5.

[0039] Specifically, in this embodiment, the frame unit 4 is divided into an upper part and a lower part. In the two frame units 4 of the upper part, the upper side of the carrier area 5 has a top pin 6 and the lower side has a bottom pin 7; in the two frame units 4 of the lower part, the lower side of the carrier area 5 has a bottom pin 7 and the upper side has a top pin 6. This symmetrical structure facilitates mold design and mass production, while ensuring that the heat dissipation paths of the left and right frame units 4 are symmetrically distributed.

[0040] Specifically, in this embodiment, a first vertical rib 9 and a second vertical rib 10 are respectively provided between the two frame units 4 in the upper part and the two frame units 4 in the lower part. It should be noted that the setting of the vertical ribs can improve the overall rigidity of the frame unit group 4, reduce deformation during stamping, ensure the stability of the height difference between the carrier area 5 and the pin area, and ensure unobstructed heat dissipation path.

[0041] Specifically, in this embodiment, the bottom pin 7 includes at least two parallel pin bodies connected by a connecting rib 11. It should be noted that the connecting rib 11 enhances the connection stability between the pins, ensures the reliability of electrical signal transmission, and prevents excessive obstruction of the heat dissipation surface of the carrier area 5 by structural components.

[0042] Specifically, in this embodiment, the central connecting area 8 has a polygonal structure with several through-holes 12 on its surface. The through-holes 12 extend along the central connecting area 8 towards each frame unit 4. It should be noted that the through-holes 12 can guide the molding compound to fill each frame unit 4 quickly and evenly, reducing air bubbles and insufficient glue, ensuring a tight bond between the encapsulation material and the substrate area 5, and improving heat conduction efficiency.

[0043] Specifically, in this embodiment, the substrate area 5 has a rectangular structure with V-grooves 13 along its edges, and flanged supports 14 on the three sides of the substrate area 5 away from the pin area. It should be noted that the V-grooves 13 enhance the bonding force between the molding compound and the substrate area 5, reducing thermal resistance; the flanged supports 14 limit and protect the chip, ensuring stable contact between the chip and the substrate area 5 and guaranteeing the effectiveness of the heat dissipation path.

[0044] Specifically, in this embodiment, the frame is provided with spaced positioning holes 15, including circular positioning holes and elliptical positioning holes, and one side of the frame is also provided with anti-reverse holes 16. It should be noted that the positioning holes 15 are used for precise positioning during the processing to ensure the relative position accuracy between the carrier area 5 and the pin area, and to ensure the consistency of the heat dissipation path design; the anti-reverse holes 16 can avoid directional errors during assembly and prevent the heat dissipation function from failing due to structural inversion.

[0045] Specifically, in this embodiment, the substrate area 5 and the top pin 6 are connected by a substrate extension area 17, which is provided with an elliptical locking groove 18 and a dovetail groove 19. It should be noted that the locking groove 18 and the dovetail groove 19 further enhance the bonding strength between the molding compound and the frame, preventing cracking after encapsulation that could lead to a decrease in heat dissipation performance.

[0046] Example:

[0047] Please see Figures 1 to 8 This novel lead frame is made of 0.5mm thick copper strip of the same profile, and includes a pair of parallel first frame 1 and second frame 2. Multiple sets of lead frame unit groups 3 are arranged side by side between the frames. Each set of lead frame unit groups 3 contains four frame units 4 arranged in a 2×2 matrix, namely the first, second, third and fourth frame units.

[0048] The first and second frame units constitute the upper half and are arranged horizontally, with the top pin 6 on the lower side and the bottom pin 7 on the upper side of their substrate area 5; the third and fourth frame units constitute the lower half and are arranged horizontally, with the bottom pin 7 on the lower side and the top pin 6 on the upper side of their substrate area 5. A first vertical rib 9 and a second vertical rib 10 are respectively provided between the two frame units 4 in the upper half and the two frame units 4 in the lower half.

[0049] It should be noted that, referring to Figure 2 and Figure 7 , Figure 2 The frame unit shown is Figure 7 Compared to the frame units shown, Figure 2 In the frame unit, the areas on the left and right sides of the bottom pin 7 are not equal, with the larger area on the left being the main electrode. Figure 7 In the frame unit, the areas on the left and right sides of the bottom pin 7 are equal, and both can be used as the main pole.

[0050] A central connection area 8 is provided at the geometric center of the four frame units. This area is a triangular structure with two apex joints, which is connected to the bottom pins 7 of each unit through the connecting rib 11.

[0051] The substrate area 5 is a rectangle measuring 6.00 × 9.00 mm², with V-grooves 13 along its edges. Except for the side connected to the substrate extension area 17, the other three sides are provided with flanged supports 14. The V-grooves 13 are 0.1 mm deep, which increases the contact area with the molding compound and reduces thermal resistance. The flanged supports 14 are 0.2 mm high, which effectively limits the chip and ensures that the bottom surface of the chip is completely attached to the substrate area 5, thereby improving heat conduction efficiency.

[0052] The substrate extension area 17 is provided with an elliptical locking groove 18 and a through dovetail groove 19, which are connected to the top pin 6. The locking groove 18 has a major axis of 3mm and a minor axis of 1.5mm, and the dovetail groove 19 is 0.8mm wide. The two work together to form a mechanical interlocking structure for the molding compound, preventing interface separation caused by thermal expansion during high-temperature operation and ensuring the stability of the heat dissipation path.

[0053] The bottom pin 7 comprises two parallel pin bodies, spaced 5.08 mm apart, connected by a connecting rib 11, which is connected to the frame. The top pin 6 comprises two pins, with the top pins 6 of adjacent frame units interconnected and connected to the frame. The plane containing the substrate area 5 and the top pin 6 is 0.3 mm lower than the plane containing the bottom pin 7, forming a stepped structure. This provides electrical isolation while allowing the back of the substrate area 5 to be directly exposed to the air, enabling rapid heat dissipation through the top heat dissipation path.

[0054] The first frame 1 has anti-reverse holes 16 with equal spacing, circular positioning holes, and elliptical positioning holes. The second frame 2 has circular positioning holes and elliptical positioning holes with equal spacing. The positional accuracy of the positioning holes 15 is controlled within ±0.02mm to ensure accurate frame positioning during stamping and packaging, guarantee the consistency of structural parameters of each unit, and thus achieve stable heat dissipation performance.

[0055] In summary, this utility model has the following beneficial effects:

[0056] Optimize the top heat dissipation path: By setting the plane where the carrier area 5 and the top pin 6 are located to be a sunken structure lower than the bottom pin 7, the back of the carrier area 5 can be directly exposed to the external environment, and heat can be directly dissipated through the metal carrier area 5, reducing thermal resistance; at the same time, the tight fit between the carrier area 5 and the chip and the limiting effect of the flange 14 ensure the stability of the heat dissipation path, solving the problem of blocked heat dissipation path in the prior art.

[0057] Improved packaging consistency and heat dissipation stability: The design of the central connection area 8 and the flow guide hole 12 enables the molding compound to flow evenly from the center to all frame units. Combined with the short flow channel design of the multi-injection head mold, it avoids the problem of uneven filling caused by the long flow channel of a single injection head, ensuring that the packaging material distribution of each frame unit is consistent, thereby ensuring the consistency of heat dissipation performance and reducing heat dissipation fluctuations caused by packaging differences.

[0058] Enhanced structural bonding and thermal conductivity: The V-shaped groove 13 of the substrate area 5, the elliptical locking groove 18 and the dovetail groove 19 of the substrate extension area 17 significantly improve the mechanical bonding force between the molding compound and the lead frame, prevent interface separation during high-temperature operation, and ensure that heat can be efficiently conducted through the close contact between the encapsulation material and the substrate area 5, solving the problem of increased thermal resistance caused by insufficient bonding force in the prior art.

[0059] Improved material utilization and process adaptability: The use of 0.5mm copper strip of the same profile for stamping reduces the material selection and processing requirements compared to profiles, saving raw material costs; at the same time, the design of at least 6 sets of lead frame units arranged in parallel, combined with the central distribution structure, can be adapted to standard multi-injection head molding molds, encapsulating more products at once, improving production efficiency, and the setting of positioning holes 15 and anti-reverse holes 16 ensures processing accuracy and guarantees structural consistency during mass production.

[0060] Strengthening structural stability and reliability: The design of the first horizontal rib 9, the second horizontal rib 10 and the connecting central rib 11 enhances the overall rigidity of the frame unit group, reduces deformation during stamping and packaging, and ensures the relative positional accuracy of the carrier area 5 and the pin area; the spacing layout of the bottom pins 7 and the rectangular design of the carrier area 5 provide a stable bearing space for the chip while ensuring electrical isolation, reducing the risk of heat dissipation failure caused by structural deformation.

[0061] The technical solutions provided by the embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of this utility model. The description of the above embodiments is only for helping to understand the principles of the embodiments of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A novel lead frame, characterized in that: It includes a pair of parallel frame edges, and at least one set of lead frame unit groups is provided between the frame edges. The lead frame unit group includes multiple frame units distributed in an array. Each frame unit includes a substrate area and a pin area. The pin area is connected to the frame edge through a connection structure. The center of the lead frame unit group is provided with a central connection area that is connected to each frame unit.

2. The novel lead frame according to claim 1, characterized in that: The lead frame unit group includes four frame units, which are arranged in a 2×2 matrix, and the central connection area is provided at the geometric center of the four frame units.

3. A novel lead frame according to claim 2, characterized in that: The pin area includes top pins and bottom pins, which are located on both sides of the substrate area. The central connection area is connected to the top pins of each frame unit.

4. A novel lead frame according to claim 3, characterized in that: The frame unit is divided into an upper part and a lower part. In the two frame units of the upper part, the upper side of the substrate area is the top pin and the lower side is the bottom pin. In the two frame units of the lower part, the lower side of the substrate area is the bottom pin and the upper side is the top pin.

5. A novel lead frame according to claim 4, characterized in that: The upper two frame units and the lower two frame units are respectively provided with a first vertical rib and a second vertical rib.

6. A novel lead frame according to claim 3, characterized in that: The bottom pin includes at least two pin bodies arranged in parallel, and the pin bodies are connected by a connecting rib.

7. A novel lead frame according to claim 1, characterized in that: The central connecting area has a polygonal structure with several through-holes on its surface. The through-holes extend along the central connecting area in the direction of each frame unit.

8. A novel lead frame according to claim 1, characterized in that: The substrate area has a rectangular structure with V-shaped grooves on its edges, and flanged supports are provided on the three sides of the substrate area away from the pin area.

9. A novel lead frame according to claim 1, characterized in that: The frame is provided with spaced positioning holes, including circular positioning holes and elliptical positioning holes, and one side of the frame is also provided with anti-reverse holes.

10. A novel lead frame according to claim 1, characterized in that: The substrate area is connected to the top pin via a substrate extension area, which is provided with an elliptical adhesive groove and a dovetail groove.

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