Lead frame and chip packaging structure
By designing a double-sided heat dissipation structure on the lead frame, and utilizing the first and second heat sinks and connectors to achieve double-sided heat dissipation for the chip and the frame, the problem of insufficient heat dissipation performance in the prior art is solved, and the heat dissipation efficiency is significantly improved.
Patent Information
- Application Number
- CN202423225153.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2026-03-03
- Estimated Expiration
- 2034-12-25
AI Technical Summary
The existing QFN package structure has insufficient heat dissipation performance, especially in terms of the difficulty in effectively dissipating heat from the lead frame, resulting in inadequate heat dissipation.
The design employs a double-sided heat dissipation structure, which includes a first heat sink attached to the back of the chip on one side of the lead frame and a second heat sink attached to the surface of the frame on the other side. The two are connected by a heat dissipation connector to form a C-shaped structure, thereby increasing the heat dissipation area and efficiency.
This achieves dual-sided heat dissipation for both the chip and the lead frame, significantly improving the heat dissipation capacity and efficiency of the QFN packaged chip and avoiding heat concentration.
Smart Images
Figure CN223968213U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of chip packaging technology, and more specifically, to a lead frame and a chip packaging structure. Background Technology
[0002] With the rapid development of the semiconductor industry, the quad flat no-lead package (QFN) structure is widely used in the semiconductor industry. When active devices such as transistors in the chip operate, they generate heat. As the number of transistors in the chip increases and the number of integrated chips increases, the heat generation also increases.
[0003] In the existing technology for QFN package structure, the conventional heat dissipation method is a single-sided heat sink design, that is, a metal heat sink cover is set on the back of the chip. However, it is difficult to dissipate the heat generated on the lead frame in time, so the heat dissipation performance is insufficient. Utility Model Content
[0004] The purpose of this invention is to provide a lead frame and chip packaging structure that can significantly improve the heat dissipation capability of QFN packaged chips and achieve double-sided heat dissipation, thereby greatly improving heat dissipation efficiency.
[0005] The embodiments of this utility model can be implemented as follows:
[0006] In a first aspect, the present invention provides a lead frame, including a frame body, a first heat sink and a second heat sink. One side surface of the frame body is provided with a mounting area for mounting a chip. The first heat sink is disposed on one side of the frame body, and at least a portion of the first heat sink is spaced apart from the frame body and is used to attach to the back side of the chip. The second heat sink is disposed on the other side of the frame body and is attached to the surface of the lead frame.
[0007] In an optional embodiment, the lead frame further includes a heat dissipation connector disposed at at least one edge of the mounting area, with one end of the heat dissipation connector connected to the first heat sink and the other end connected to the second heat sink.
[0008] In an optional embodiment, the frame body is further provided with a clearance groove, which is located on one side edge of the mounting area and extends through the frame body, and the heat dissipation connector passes through the clearance groove.
[0009] In an optional embodiment, one end of the heat dissipation connector is flush with the first heat sink and connected to one side edge of the first heat sink, and the other end of the heat dissipation connector is flush with the second heat sink and connected to one side edge of the second heat sink.
[0010] In an optional embodiment, the heat dissipation connector is provided with a plurality of first heat dissipation fins on the side near the mounting area. The plurality of first heat dissipation fins are spaced apart from each other and form a plurality of first heat dissipation grooves. The plurality of first heat dissipation fins are used to extend toward the sidewall of the chip.
[0011] In an optional embodiment, the heat dissipation connector is further provided with a plurality of second heat dissipation fins on the side away from the mounting area. The plurality of second heat dissipation fins are spaced apart from each other and form a plurality of second heat dissipation grooves, and the plurality of second heat dissipation fins are used to extend away from the sidewall of the chip.
[0012] In an optional embodiment, the extension width of the first heat dissipation fin is greater than the extension width of the second heat dissipation fin.
[0013] In an optional embodiment, a plurality of the first heat dissipation fins are spaced apart and parallel to each other, and the edges of the plurality of the first heat dissipation fins are flush with each other, and are used to abut against the sidewall of the chip to position the chip.
[0014] In an optional embodiment, a plurality of pins are provided on the other side of the frame body, and the plurality of pins surround the second heat sink.
[0015] Secondly, this utility model provides a chip packaging structure, including a chip, a molding compound, and a lead frame as described in any of the foregoing embodiments. The chip is flip-chip bonded to the mounting area of the frame body, a first heat sink is bonded to the back of the chip, and the molding compound is disposed on the frame body and covers the chip.
[0016] The beneficial effects of the lead frame and chip packaging structure provided in this embodiment of the present invention include:
[0017] The lead frame provided in this embodiment of the invention has a mounting area on one side surface of the frame body, where a chip can be mounted. A first heat sink is disposed on one side of the frame body and attached to the back of the chip, thereby achieving heat dissipation for the chip. Simultaneously, a second heat sink is disposed on the other side of the frame body, which is attached to the surface of the lead frame, thereby achieving heat dissipation for the lead frame. Compared to the prior art, the lead frame provided in this embodiment of the invention can simultaneously achieve heat dissipation for both the chip and the lead frame through the arrangement of the first and second heat sinks, significantly improving the heat dissipation capability of the QFN packaged chip and achieving double-sided heat dissipation, resulting in a substantial improvement in heat dissipation efficiency. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 A schematic diagram of the lead frame provided in an embodiment of the present utility model from a first perspective;
[0020] Figure 2 A schematic diagram of the lead frame provided in an embodiment of the present utility model from a second perspective;
[0021] Figure 3 A schematic diagram of the lead frame provided in an embodiment of this utility model from a third-view perspective;
[0022] Figure 4 A partial structural schematic diagram of the lead frame provided in an embodiment of this utility model;
[0023] Figure 5 This is a schematic diagram of the overall structure of the chip packaging structure provided in an embodiment of the present utility model.
[0024] Icons: 100 - Lead frame; 110 - Frame body; 111 - Recessed groove; 113 - Pin; 130 - First heat sink; 150 - Second heat sink; 170 - Heat dissipation connector; 171 - First heat dissipation fin; 173 - First heat dissipation recess; 175 - Second heat dissipation fin; 177 - Second heat dissipation recess; 200 - Chip package structure; 210 - Chip; 230 - Molded enclosure. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0028] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0029] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.
[0030] As disclosed in the background section, existing packaging structures typically involve mounting a chip on a leadframe and attaching a metal heat sink to the back of the chip to dissipate heat from the back of the chip. However, since current also flows through the leadframe, it generates a significant amount of heat. Current solutions cannot effectively dissipate heat from the leadframe, leading to heat concentration issues that negatively impact device performance.
[0031] To address the aforementioned problems, this utility model provides a novel lead frame and chip packaging structure. It should be noted that, unless otherwise specified, the features in the embodiments of this utility model can be combined with each other.
[0032] See Figures 1 to 4 This utility model embodiment provides a lead frame 100, which, through a double-sided heat dissipation structure design, can significantly improve the heat dissipation capability of the QFN packaged chip 210 and achieve double-sided heat dissipation, thus greatly improving heat dissipation efficiency.
[0033] The lead frame 100 provided in this embodiment of the present invention includes a frame body 110, a first heat sink 130 and a second heat sink 150. One side surface of the frame body 110 is provided with a mounting area for mounting a chip 210. The first heat sink 130 is disposed on one side of the frame body 110, and at least a portion of the first heat sink 130 is spaced apart from the frame body 110 and is used to attach to the back side of the chip 210. The second heat sink 150 is disposed on the other side of the frame body 110 and is attached to the surface of the lead frame 100.
[0034] It should be noted that the lead frame 100 is suitable for QFN package structures. During actual packaging, the chip 210 is mounted on the mounting area of the frame body 110. The first heat sink 130 is in close contact with the back of the chip 210 and exposed after molding, thus directly dissipating heat from the chip 210. Furthermore, the second heat sink 150 is in close contact with the surface of the frame body 110 opposite to the chip 210, thereby dissipating heat from the frame body 110 and preventing heat concentration on the frame body 110. This significantly improves the heat dissipation capacity of the QFN packaged chip 210 and enables double-sided heat dissipation, greatly improving heat dissipation efficiency.
[0035] Specifically, both the first heat sink 130 and the second heat sink 150 can be heat sinks made of thermally conductive metals, such as indium or copper, to ensure their heat dissipation effect.
[0036] In some embodiments, the lead frame 100 further includes a heat dissipation connector 170, which is disposed at at least one edge of the mounting area. One end of the heat dissipation connector 170 is connected to the first heat sink 130, and the other end is connected to the second heat sink 150. Specifically, the heat dissipation connector 170 may be made of the same metal material as the first heat sink 130 or the second heat sink 150. On the one hand, it can play a structural support role, thereby ensuring a stable connection between the first heat sink 130 and the second heat sink 150. On the other hand, it can also play a heat transfer role, so that the heat on the lead frame 100 after the upper board is packaged can be transferred from the second heat sink 150 to the first heat sink 130, further improving its heat dissipation effect.
[0037] It should be noted that the heat dissipation connector 170 here can connect the first heat sink 130 and the second heat sink 150 into a whole, thereby greatly increasing the overall heat dissipation area. When the heat generated by the chip 210 increases significantly, the heat generated by the chip 210 can be conducted to the second heat sink 150 on the back, thereby achieving heat dissipation on the back.
[0038] Furthermore, the frame body 110 also has a clearance groove, which is located at least one edge of the mounting area and extends through the frame body 110. The heat dissipation connector 170 passes through the clearance groove. Specifically, the clearance groove is located on one edge of the mounting area, thereby defining the approximate range of the mounting area and facilitating accurate mounting of the chip 210. In other preferred embodiments of this invention, the clearance groove may also be located on both sides of the mounting area, so that the heat dissipation connector 170 is located on both sides of the chip 210, thereby achieving better support and heat dissipation.
[0039] In some embodiments, one end of the heat dissipation connector 170 is flush with the first heat sink 130 and connected to one side edge of the first heat sink 130, and the other end of the heat dissipation connector 170 is flush with the second heat sink 150 and connected to one side edge of the second heat sink 150. Specifically, both ends of the heat dissipation connector 170 are respectively connected to the first heat sink 130 and the second heat sink 150 and are respectively flush with the first heat sink 130 and the second heat sink 150, and are located at one side edge of the first heat sink 130 and the second heat sink 150, which can form a C-shaped structure, avoiding interference between the first heat sink 130 and the position of the chip 210 while ensuring the structural stability of the first heat sink 130 and the second heat sink 150.
[0040] In some embodiments, the heat dissipation connector 170 has a plurality of first heat dissipation fins 171 on the side near the mounting area. The plurality of first heat dissipation fins 171 are spaced apart from each other and form a plurality of first heat dissipation grooves 173. The plurality of first heat dissipation fins 171 are used to extend toward the sidewall of the chip 210. Specifically, the plurality of first heat dissipation fins 171 are spaced apart and parallel to each other, and the edges of the plurality of first heat dissipation fins 171 are flush with each other, and are used to abut against the sidewall of the chip 210 to position the chip 210. The plurality of first heat dissipation fins 171 are integrally disposed on the sidewall of the heat dissipation connector 170, and a first heat dissipation groove 173 is formed between two adjacent first heat dissipation fins 171. The design of the first heat dissipation groove 173 can increase the heat exchange area of the heat dissipation connector 170, thereby improving the heat dissipation effect of the heat dissipation connector 170. In addition, multiple first heat dissipation fins 171 can abut against the sidewall of chip 210, so when chip 210 is mounted, multiple first heat dissipation fins 171 can be used to position chip 210, improving mounting accuracy.
[0041] In some embodiments, a plurality of second heat dissipation fins 175 are further provided on the side of the heat dissipation connector 170 away from the mounting area. The plurality of second heat dissipation fins 175 are spaced apart from each other and form a plurality of second heat dissipation grooves 177, and the plurality of second heat dissipation fins 175 are extended away from the sidewall of the chip 210. Specifically, the plurality of second heat dissipation fins 175 are disposed on both sides of the heat dissipation connector 170 in a one-to-one correspondence with the plurality of first heat dissipation fins 171. The plurality of second heat dissipation fins 175 are parallel to each other, and the edges of the plurality of second heat dissipation fins 175 are flush with each other, so that the molding compound after molding can flow evenly into the first heat dissipation grooves 173 and the second heat dissipation grooves 177 to achieve filling and improve the bonding force of the molding compound 230.
[0042] In some embodiments, the extension width of the first heat dissipation fin 171 is greater than the extension width of the second heat dissipation fin 175. Specifically, the greater extension width of the first heat dissipation fin 171 results in stronger heat dissipation capacity of the heat dissipation fins near the sidewall of the chip 210, enabling more rapid and effective heat dissipation of the chip 210.
[0043] In some embodiments, a plurality of pins 113 are provided on the other side of the frame body 110, and the plurality of pins 113 surround the second heat sink 150. Specifically, the frame body 110 in this embodiment is suitable for a QFN package structure, and the edge of the frame body 110 is provided with a plurality of pins 113, which can surround the second heat sink 150 and be spaced apart from the second heat sink 150, thereby avoiding short circuits.
[0044] See Figure 5 This utility model embodiment also provides a chip packaging structure 200, including a chip 210, a molding compound 230, and the aforementioned lead frame 100. The lead frame 100 includes a frame body 110, a first heat sink 130, and a second heat sink 150. One side surface of the frame body 110 is provided with a mounting area for mounting the chip 210. The first heat sink 130 is disposed on one side of the frame body 110, and at least a portion of the first heat sink 130 is spaced apart from the frame body 110 and is used to attach to the back side of the chip 210. The second heat sink 150 is disposed on the other side of the frame body 110 and is attached to the surface of the lead frame 100. The chip 210 is flip-chip mounted on the mounting area of the frame body 110, the first heat sink 130 is attached to the back side of the chip 210, and the molding compound 230 is disposed on the frame body 110 and covers the chip 210.
[0045] In some embodiments, the molding compound 230 is flush with the first heat sink 130, thereby exposing the first heat sink 130 and improving heat dissipation. At the same time, the molding compound 230 can cover the heat dissipation connector 170, improving the bonding force between the molding compound 230 and the lead frame 100.
[0046] In summary, the lead frame 100 and chip packaging structure 200 provided in this embodiment of the present invention have a mounting area on one side surface of the frame body 110, where a chip 210 can be mounted. A first heat sink 130 is disposed on one side of the frame body 110 and attached to the back of the chip 210, thereby achieving heat dissipation for the chip 210. Simultaneously, a second heat sink 150 is disposed on the other side of the frame body 110, which can be attached to the surface of the lead frame 100, thereby achieving heat dissipation for the lead frame 100. Compared to the prior art, the lead frame 100 provided in this embodiment of the present invention can simultaneously achieve heat dissipation for both the chip 210 and the lead frame 100 through the arrangement of the first heat sink 130 and the second heat sink 150, significantly improving the heat dissipation capacity of the QFN packaged chip 210 and achieving double-sided heat dissipation, thus greatly improving heat dissipation efficiency.
[0047] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.
Claims
1. A leadframe, characterized by, The lead frame comprises a frame body, a first heat sink and a second heat sink, one side surface of the frame body is provided with a mounting area for mounting a chip, the first heat sink is arranged on one side of the frame body and at least part of the first heat sink is spaced apart from the frame body and used for being attached to the back surface of the chip, and the second heat sink is arranged on the other side of the frame body and attached to the surface of the lead frame. The lead frame further comprises a heat dissipation connecting piece, the heat dissipation connecting piece is arranged on at least one side edge of the mounting area, one end of the heat dissipation connecting piece is connected to the first heat sink, and the other end of the heat dissipation connecting piece is connected to the second heat sink.
2. The leadframe of claim 1, wherein, The frame body is further provided with a recess, the recess is arranged on one side edge of the mounting area and penetrates through the frame body, and the heat dissipation connecting piece is arranged in the recess.
3. The leadframe of claim 1, wherein, One end of the heat dissipation connecting piece is flush with the first heat sink and connected to one side edge of the first heat sink, and the other end of the heat dissipation connecting piece is flush with the second heat sink and connected to one side edge of the second heat sink.
4. The leadframe of claim 1, wherein, The heat dissipation connecting piece is provided with a plurality of first heat dissipation fins on one side close to the mounting area, the plurality of first heat dissipation fins are arranged at intervals and form a plurality of first heat dissipation grooves, and the plurality of first heat dissipation fins are used for extending towards the side wall of the chip.
5. The leadframe of claim 4, wherein, The heat dissipation connecting piece is further provided with a plurality of second heat dissipation fins on one side away from the mounting area, the plurality of second heat dissipation fins are arranged at intervals and form a plurality of second heat dissipation grooves, and the plurality of second heat dissipation fins are used for extending away from the side wall of the chip.
6. The leadframe of claim 5, wherein, The extension width of the first heat dissipation fin is greater than the extension width of the second heat dissipation fin.
7. The leadframe of claim 4, wherein, The plurality of first heat dissipation fins are parallel to each other at intervals, the edges of the plurality of first heat dissipation fins are flush with each other, and the edges are used for abutting against the side wall of the chip to position the chip.
8. The leadframe of claim 1, wherein, The other side of the frame body is provided with a plurality of pins, and the plurality of pins are arranged around the second heat sink.
9. A chip package structure, characterized by, The lead frame comprises a chip, a plastic encapsulation body and the lead frame according to any one of claims 1-8, the chip is flip-chip mounted on the mounting area of the frame body, the first heat sink is attached to the back surface of the chip, and the plastic encapsulation body is arranged on the frame body and encapsulates the chip.