Lead frame and packaging structure
By designing a heat dissipation structure and bent leads on the lead frame away from the chip side, the problem of heat accumulation in semiconductor packaging is solved, achieving efficient heat dissipation and optimized electrical performance, extending the chip's lifespan and improving the reliability and performance of electronic devices.
Patent Information
- Application Number
- CN202520211471.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-11
- Publication Date
- 2025-12-12
- Estimated Expiration
- 2035-02-11
AI Technical Summary
In existing semiconductor packaging, the poor thermal conductivity of materials such as resin leads to an increase in the operating temperature of the chip, which affects the reliability of solder joints and interconnects, reduces the chip's lifespan, and alters its electrical performance.
A heat dissipation structure is set on the side of the lead frame away from the chip, and is electrically connected to the chip through a bent pin. The free end of the bent pin is away from the heat dissipation structure, forming a path for rapid heat dissipation.
It effectively reduces chip operating temperature, improves the reliability of solder joints and interconnects, extends chip lifespan, optimizes electrical performance and mechanical stability, and enhances thermal management efficiency, making it suitable for high-performance and high-reliability electronic devices.
Smart Images
Figure CN223665450U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor packaging technology, and more specifically, to a lead frame and packaging structure. Background Technology
[0002] In semiconductor packaging, a molding compound is typically used to protect the chip and enhance its safety. Because chips generate significant heat during operation, and materials like resin have poor thermal conductivity, the operating temperature of the chip rises. Excessively high operating temperatures accelerate material aging, reduce the reliability of solder joints and interconnects, and may even cause physical damage to the packaging material and the chip itself, reducing its lifespan. Furthermore, as temperature increases, the carrier mobility in semiconductor materials decreases, leading to changes in the chip's electrical performance. For example, the switching speed of transistors may slow down, and leakage current may increase, thus affecting the performance of the entire circuit. Utility Model Content
[0003] The purpose of this application is to provide a lead frame and a packaging structure, which can effectively enhance the heat dissipation performance of the packaging structure and avoid heat accumulation by setting heat dissipation structure components on the side of the lead frame away from the chip.
[0004] The embodiments of this application are implemented as follows:
[0005] In a first aspect, embodiments of this application provide a lead frame, including a metal frame body, one side surface of which has an effective bearing surface for mounting a chip; the metal frame body has a heat dissipation structure on the side opposite to the effective bearing surface; the metal frame body has bent pins electrically connected to the chip, the bending pins extending in a direction perpendicular to the effective bearing surface, and the free end of the bent pins being away from the heat dissipation structure.
[0006] As an optional implementation, the metal frame body includes a central base island; the effective bearing surface is located on the surface of the central base island; the bent pin is separated from the central base island at one end near the chip to form a gap, so that the bent pin forms a connection terminal; the connection terminal is connected to the chip via a wire.
[0007] As an optional implementation, there are at least two metal frame bodies; at least two metal frame bodies are stacked; and the connecting terminals are connected to corresponding connecting terminals on adjacent metal frame bodies.
[0008] As an optional implementation, the free end of the bent pin forms a bent portion, which is used to increase the contact surface between two adjacent connection terminals.
[0009] As an optional implementation, the chip is projected into a contact surface between the heat dissipation structure and the metal frame body.
[0010] As an optional implementation, the heat dissipation structure is connected to the metal frame body through an adhesive layer.
[0011] As an optional implementation, the bent pin is multiple and arranged in a circumferential direction.
[0012] As an optional implementation, the bent pin includes any one of a C-shaped structure, a U-shaped structure, an I-shaped structure and an L-shaped structure.
[0013] In a second aspect, an embodiment of the present application provides a packaging structure, including the lead frame, the chip and the plastic encapsulation layer.
[0014] As an optional implementation, the free end of the bent pin is flush with or protrudes from the surface of the plastic encapsulation layer.
[0015] The beneficial effects of the embodiments of the present application include:
[0016] In a first aspect, an embodiment of the present application provides a lead frame, including a metal frame body, a side surface of the metal frame body having an effective bearing surface for mounting a chip; the metal frame body being provided with a heat dissipation structure on a side away from the effective bearing surface; the metal frame body being provided with a bent pin electrically connected to the chip, the bent pin extending in a direction perpendicular to the effective bearing surface, and a free end of the bent pin being away from the heat dissipation structure.
[0017] In a second aspect, an embodiment of the present application provides a packaging structure, including the lead frame, the chip and the plastic encapsulation layer; the chip being mounted on the effective bearing surface; and the plastic encapsulation layer covering the chip and the bent pin on the metal frame body. BRIEF DESCRIPTION OF DRAWINGS
[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as a limitation to the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.
[0019] Figure 1 Fig. 1 is a structural schematic diagram of a lead frame according to an embodiment of the present application;
[0020] Figure 2 Fig. 2 is another structural schematic diagram of a lead frame according to an embodiment of the present application;
[0021] Figure 3 Fig. 3 is a third structural schematic diagram of a lead frame according to an embodiment of the present application;
[0022] Figure 4 Fig. 4 is a fourth structural schematic diagram of a lead frame according to an embodiment of the present application;
[0023] Figure 5 Fig. 5 is a fifth structural schematic diagram of a lead frame according to an embodiment of the present application;
[0024] Figure 6 Fig. 6 is a sixth structural schematic diagram of a lead frame according to an embodiment of the present application.
[0025] Fig. 1 is a structural schematic diagram of a lead frame according to an embodiment of the present application; DETAILED DESCRIPTION
[0026] So that the objects, technical solutions and advantages of the embodiments of the present application are more apparent, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.
[0027] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.
[0028] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, the terms "first", "second", "third" and the like are only used to distinguish description, and cannot be understood as indicating or implying relative importance.
[0029] It should be noted that, in the description of the present application, unless otherwise explicitly specified and limited, the terms "set", "install", "connect", "connect" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0030] In semiconductor packaging, in order to improve the safety of the chip, the chip is usually packaged and protected by a plastic sealing layer. Because a large amount of heat is generated during the work of the chip, and the thermal conductivity of the resin and other materials is poor, the temperature of the chip working environment is increased. The high working temperature can accelerate the aging process of the material, reduce the reliability of the solder joints and connecting lines, and even cause physical damage to the packaging material and the chip itself, thereby reducing the service life of the chip. In addition, as the temperature rises, the carrier mobility in the semiconductor material will decrease, which will cause the electrical performance of the chip to change. For example, the switching speed of the transistor can be slowed down, and the leakage current is increased, thereby affecting the performance of the entire circuit.
[0031] To solve the above technical problems, the embodiments of the present application provide a lead frame and a packaging structure.
[0032] Referring to FIGS. 1 to 3, Figure 1 , Figure 2 The lead frame provided by the embodiments of the present application includes a metal frame body 100, one side surface of the metal frame body 100 has an effective bearing surface 101 for mounting a chip 110; the metal frame body 100 is provided with a heat dissipation structure 102 on the side away from the effective bearing surface 101; the metal frame body 100 has a bent pin 103 electrically connected to the chip 110, the extension direction of the bent pin 103 is perpendicular to the effective bearing surface 101, and the free end 104 of the bent pin 103 is away from the heat dissipation structure 102.
[0033] It should be noted that the metal frame body 100 of the embodiments of the present application has an effective bearing surface 101 for mounting a chip 110 on one side surface. The heat dissipation structure 102 is located on the side of the metal frame body 100 away from the effective bearing surface 101, that is, it is provided on the back of the lead frame. The design of the embodiments of the present application allows heat to be directly conducted from the chip 110 to the heat dissipation structure 102 through the metal frame, and then dissipated to the environment. That is, the heat transfer process of the embodiments of the present application is from the chip 110 to the metal frame body 100 and then to the heat dissipation structure 102.
[0034] In the embodiment of the present application, the chip 110 is attached to the effective bearing surface 101 of the metal frame body 100, and the heat dissipation structure 102 is attached to the metal frame body 100. Therefore, the embodiment of the present application can form a heat transfer channel with a large cross-sectional area, achieving efficient heat conduction.
[0035] The bent pin 103 of the embodiment of the present application is electrically connected to the chip 110 and is bent away from the heat dissipation structure 102, finally forming a connection terminal 106 that can be used to connect an external circuit board. In the embodiment of the present application, the bent pin 103 exists as a connection terminal 106, and the electrical connection between the chip 110 and the external circuit board is achieved through the bent pin 103.
[0036] The embodiment of the present application can produce the following beneficial effects:
[0037] First, efficient heat dissipation. By arranging the heat dissipation structure 102 on the back of the lead frame, the heat generated by the chip 110 during operation can be effectively and quickly conducted out, reducing the operating temperature of the chip 110, thereby slowing down the material aging process, improving the reliability of the solder joints and connection lines, and prolonging the service life of the chip 110.
[0038] Second, optimizing electrical performance. Reducing the operating temperature of the chip 110 helps maintain the carrier mobility in the semiconductor material, maintains the switching speed of the transistor, reduces the leakage current, and thus ensures the stable performance of the entire circuit.
[0039] Third, enhancing mechanical stability. Due to the design of the bent pin 103, the lead frame can be mounted on the circuit board in a flip-chip manner, which not only facilitates heat dissipation but also enhances the overall mechanical connection stability.
[0040] In addition, compared with the traditional packaging method, the embodiment of the present application significantly improves the heat management efficiency and reduces various problems caused by overheating, such as material aging and electrical performance degradation. In addition, the embodiment of the present application allows the lead frame to be mounted on the circuit board in a flip-chip manner, which not only facilitates heat dissipation but also provides greater flexibility for circuit board design. Overall, this design improves the reliability and performance of electronic products, and also helps to reduce the size of the device, adapting to the demand for miniaturization and high performance of modern electronic products.
[0041] Referring to Figure 2 , Figure 3 As an optional implementation, the metal frame body 100 includes a central base island 105; the effective bearing surface 101 is located on the surface of the central base island 105; the bent pin 103 is separated from the central base island 105 at one end near the chip 110 to form a spacing, so that the bent pin 103 forms a connection terminal 106; the connection terminal 106 is connected to the chip 110 through a wire 107.
[0042] It should be noted that the metal frame body 100 comprises a central base island 105, and the effective bearing surface 101 of the chip 110 is located on the surface of the central base island 105. The geometric center of the central base island 105 can coincide with the geometric center of the metal frame body 100 according to the needs of those skilled in the art. The geometric center of the central base island 105 can also have a spacing with the geometric center of the whole metal frame body 100.
[0043] The shape of the central base island 105 can be a square or other shapes.
[0044] It should be noted that the bent pin 103 is separated from the central base island 105.
[0045] In order to increase electrical isolation and reduce the interference of the heat conduction path, the end of the bent pin 103 close to the chip 110 is separated from the central base island 105, forming a spacing. This allows the bent pin 103 to form an independent connection terminal 106. The electrical connection between the chip 110 and the connection terminal 106 formed by the bent pin 103 is realized by the wire 107. These wires 107 are responsible for transmitting signals and power, ensuring that the chip 110 can communicate with the external circuit board.
[0046] It should be noted that the central base island 105 can be separated from the bent pin 103 by cutting. When cutting, the connection root of the bent pin 103 and the central base island 105 can be directly cut off. It should be noted that the bent portion 108 of the bent pin 103 can have a predetermined spacing with the connection root, or the bent portion 108 of the bent pin 103 and the connection root. Those skilled in the art can choose according to the needs.
[0047] It should be noted that the separation spacing between the bent pin 103 and the central base island 105 can be set by those skilled in the art according to the needs, and no special limitation is made.
[0048] The beneficial effects that can be produced by the embodiments of the present application are:
[0049] The embodiments of the present application separate the bent pin 103 from the central base island 105, increase the electrical isolation degree, reduce the interference between different circuits, and improve the signal integrity and reliability.
[0050] In the embodiments of the present application, since the bent pin 103 is separated from the central base island 105, the heat transfer process from the chip 110 to the heat dissipation structure 102 is more direct and effective, avoiding the problem of overheating of other components caused by heat conduction through the pin, and further improving the heat dissipation efficiency.
[0051] The embodiment of this application uses wire 107 for connection, which allows designers greater freedom in layout. The connection position and method between chip 110 and bent pin 103 can be adjusted according to actual needs to adapt to different application scenarios.
[0052] Overall, the embodiments of this application not only solve the problems of thermal management and electrical performance, but also provide greater flexibility and manufacturing convenience through improved design, which helps to improve the reliability and performance of the entire electronic device.
[0053] Reference Figure 2 , Figure 6 As shown, as an optional implementation, there are at least two metal frame bodies 100; at least two metal frame bodies 100 are stacked; and the connecting terminals 106 are connected to the connecting terminals 106 on the adjacent metal frame bodies 100.
[0054] It should be noted that there are at least two metal frame bodies 100 in this embodiment, and these metal frame bodies 100 are stacked. This means that multiple chips 110 can be mounted on different metal frame bodies 100 to form a multi-layer structure.
[0055] For example, refer to Figure 6 As shown, there are three metal frame bodies 100; the three metal frame bodies 100 are stacked; the connecting terminals 106 are connected to the connecting terminals 106 on the adjacent metal frame bodies 100.
[0056] It should be noted that the connection terminals 106 formed by the bent pins 103 on each metal frame body 100 correspond to and are electrically connected to the connection terminals 106 on the adjacent metal frame bodies 100. In this way, even in a multi-layer structure, electrical connectivity between layers can be ensured.
[0057] The beneficial effects that the embodiments of this application can produce are as follows:
[0058] The embodiments of this application increase the number of chips 110 or functional modules by stacking, which can expand the function and performance of the circuit without increasing the package area, greatly improving space utilization and making it particularly suitable for application scenarios that require high-density integration.
[0059] The embodiments of this application can enhance functionality and flexibility. The multi-layer stacked structure of the embodiments of this application allows more chips 110 or modules with different functions, such as logic processing and storage, to be integrated in one package, thereby improving the functionality and design flexibility of the entire electronic device.
[0060] The embodiments of this application can optimize the signal transmission path. Since the connection terminals 106 are directly connected, the signal transmission distance is shortened, signal delay and loss are reduced, and the integrity of high-speed data transmission is maintained.
[0061] The embodiments of this application can simplify system complexity. Compared with using multiple individually packaged chips 110, this stacked design can reduce the number of external connections, simplify the design complexity of the circuit board, and also help reduce manufacturing costs.
[0062] Reference Figure 4 , Figure 5 as well as Figure 6 As shown, as an optional implementation, the free end 104 of the bent pin 103 forms a bent portion 108, which is used to increase the contact surface of two adjacent connection terminals 106.
[0063] It should be noted that, in this embodiment, the bent pin 103 forms a bend 108 at its free end 104. The purpose of this bend 108 is to increase the contact surface between two adjacent connection terminals 106. This means that when the multi-layer metal frame bodies 100 are stacked, the connection terminals 106 of the upper and lower layers achieve a more stable and reliable electrical connection through the bend 108.
[0064] This embodiment of the application significantly improves the reliability and stability of electrical connections by increasing the contact area between two adjacent connection terminals 106. A larger contact area means lower contact resistance and better conductivity, reducing signal loss or interference problems caused by poor contact.
[0065] The bent portion 108 in this embodiment not only increases the electrical connection strength but also enhances the robustness of the mechanical connection. This is particularly important for electronic devices that require long-term stable operation, especially in application environments where vibration or impact may occur.
[0066] Furthermore, the embodiments of this application simplify alignment accuracy. The larger contact surface can, to some extent, relax the requirements for precise alignment during manufacturing and assembly, because even minor positional deviations will not significantly affect the final electrical connection quality. This helps reduce production difficulty and costs.
[0067] As an optional implementation, the heat dissipation structure 102 is connected to the metal frame body 100 via an adhesive layer.
[0068] The chip 110 is projected into the contact surface between the heat dissipation structure 102 and the metal frame body 100.
[0069] As an optional implementation, the bent pin 103 is multiple and arranged in a circumferential direction of the chip 110.
[0070] The bent pin 103 includes any one of a C-shaped structure, a U-shaped structure, an I-shaped structure, and an L-shaped structure.
[0071] It should be noted that the specific structure of the bent pin 103 can be selected as needed by those skilled in the art.
[0072] Referring to Figure 2 The embodiment of the present application provides a packaging structure, which includes the lead frame, the chip 110, and the plastic encapsulation layer 109; the chip 110 is attached to the effective bearing surface 101; and the plastic encapsulation layer 109 covers the chip 110 and the bent pin 103 on the metal frame body 100.
[0073] It should be noted that the free end 104 of the bent pin 103 of the embodiment of the present application is flush with or protrudes from the surface of the plastic encapsulation layer 109.
[0074] The embodiment of the present application covers the chip 110 and the bent pin 103 by setting the plastic encapsulation layer 109 on the metal frame body 100, which can effectively prevent the erosion of the internal components by the external environment, provide physical protection, and enhance the durability and reliability of the entire packaging structure.
[0075] The bent pin 103 of the embodiment of the present application protrudes from the surface of the plastic encapsulation layer 109, which can facilitate welding or other forms of electrical connection on the external circuit board. The protruding design helps to improve the welding quality, as it provides a more explicit contact point, which is conducive to precise positioning and connection on the automated production line.
[0076] In addition, since the heat dissipation structure 102 is arranged on the side of the metal frame body 100 away from the chip 110, and the lead frame is installed in an inverted manner, the heat dissipation structure 102 can be directly in contact with the external environment, achieving efficient heat conduction and dissipation. This reduces the overall temperature rise caused by the heat generated by the chip 110 during operation, thereby prolonging the service life of the electronic components and improving the performance stability.
[0077] The design of the bent pin 103 of the embodiment of the present application being flush with or slightly protruding from the surface of the plastic encapsulation layer 109 takes into account the ease of operation in the subsequent assembly process, which not only ensures the integrity of the packaging structure, but also facilitates the connection with other electronic components, reduces the manufacturing complexity, and is suitable for mass production.
[0078] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A leadframe, characterized by, The metal frame body includes a side surface with an effective bearing surface for mounting a chip; the metal frame body is provided with a heat dissipation structure on the side away from the effective bearing surface; the metal frame body has a bent pin electrically connected to the chip, the bent pin extends perpendicularly to the effective bearing surface, and the free end of the bent pin is away from the heat dissipation structure.
2. The leadframe of claim 1, wherein, The metal frame body includes a central base island; the effective bearing surface is located on the surface of the central base island; the bent pin is separated from the central base island at the end close to the chip to form a spacing, so that the bent pin forms a connecting terminal; the connecting terminal is connected to the chip by a wire.
3. The leadframe of claim 2, wherein, The metal frame body includes at least two; at least two metal frame bodies are stacked; the connecting terminal is connected to the connecting terminal on the adjacent metal frame body.
4. The leadframe of claim 2, wherein, The free end of the bent pin forms a bent part for increasing the contact surface of the two adjacent connecting terminals.
5. The leadframe of any one of claims 1-4, wherein, The chip is projected into the contact surface of the heat dissipation structure and the metal frame body.
6. The leadframe of any one of claims 1-4, wherein, The heat dissipation structure is connected to the metal frame body by an adhesive layer.
7. The leadframe of any one of claims 1-4, wherein, The bent pin has multiple and is arranged circumferentially around the chip.
8. The leadframe of any of claims 2-4, wherein, The bent pin includes any one of C-shaped structure, U-shaped structure, I-shaped structure and L-shaped structure.
9. A package structure, characterized by, The lead frame includes the lead frame of any one of claims 1-8, a chip and a plastic encapsulation layer; the chip is mounted on the effective bearing surface; the plastic encapsulation layer covers the chip and the bent pin on the metal frame body.
10. The package structure of claim 9, wherein, The free end of the bent pin is flush with the surface of the plastic encapsulation layer or protrudes from the surface of the plastic encapsulation layer.