MOSFET heat dissipation structure and circuit board

Abstract

The utility model relates to an MOSFET heat dissipation structure and a circuit board. The MOSFET heat dissipation structure comprises an MOSFET chip which is arranged on a circuit board, the MOSFET heat dissipation structure further comprises a metal sheet assembly and one or more heat conduction pieces. The metal sheet assembly comprises a top metal sheet and a bottom metal sheet. The MOSFET chip is provided with a top heat dissipation window; the top metal sheet is precisely attached to the top heat dissipation window to form a top heat dissipation path so as to dissipate heat generated in the MOSFET from the top heat dissipation path; the bottom of the MOSFET chip is arranged close to the top of the circuit board, the bottom metal sheet is arranged close to the bottom of the circuit board, and the bottom of the MOSFET chip and the bottom metal sheet are connected in a heat transfer mode through the heat conduction piece to form a bottom heat dissipation path. The top metal sheet and the bottom metal sheet are connected with each other to form a complete heat dissipation path. According to the MOSFET heat dissipation structure, the thermal resistance can be remarkably reduced, and the heat dissipation efficiency is improved; the over-current capability is enhanced, and the method is suitable for high-power scenes.

Description

Technical Field

[0001] This application relates to the field of electronic components technology, and in particular to a MOSFET heat dissipation structure and circuit board. Background Technology

[0002] MOSFETs are widely used in electronic devices, especially in high-current applications, where their internal resistance leads to significant heat generation. According to the heat power formula P=I²R, the greater the current through the MOSFET, the greater the heat generated. MOSFETs are soldered to the circuit board at the bottom. Traditional MOSFET heat dissipation structures typically employ bottom or top cooling methods, but these methods have limitations in heat dissipation efficiency and current carrying capacity. Especially in high-power applications, insufficient heat dissipation can lead to excessively high device temperatures, affecting their performance and lifespan.

[0003] Traditional bottom heat dissipation structures dissipate heat through the copper layer of the circuit board. The heat generated by the MOSFET is transferred to the circuit board at the bottom of the MOSFET through the MOSFET pins, and then dissipated to the environment through the copper layer of the circuit board. However, due to the limited thermal conductivity of the circuit board, the heat dissipation rate is low.

[0004] Traditional top heat dissipation structures dissipate heat through the encapsulation resin on top of the MOSFET. The heat generated by the MOSFET core is transferred through the encapsulation resin to the thermal grease on the top layer of the MOSFET, and then dissipates heat outward from the thermal grease. However, due to the poor thermal conductivity of the MOSFET encapsulation resin and the long heat dissipation path, the heat dissipation efficiency is low.

[0005] Because traditional MOSFET heat dissipation structures have low heat dissipation efficiency, MOSFETs are prone to excessive temperature rise due to insufficient heat dissipation in high-power scenarios, which affects performance and lifespan. Therefore, there is a great need for a heat dissipation structure that can effectively improve the heat dissipation efficiency and overcurrent capacity of MOSFETs. Utility Model Content

[0006] The technical problem to be solved by this application is to provide a MOSFET heat dissipation structure that solves the problems of low heat dissipation efficiency and insufficient overcurrent capacity of existing MOSFET heat dissipation structures.

[0007] To solve the above-mentioned technical problems, this application adopts the following technical solution:

[0008] A MOSFET heat dissipation structure includes a MOSFET chip disposed on a circuit board; the MOSFET heat dissipation structure further includes a metal sheet assembly and one or more heat-conducting components, the metal sheet assembly including a top metal sheet and a bottom metal sheet; the MOSFET chip has a top heat dissipation window; the top metal sheet and the top heat dissipation window are precisely fitted to form a top heat dissipation path to dissipate heat generated inside the MOSFET from the top heat dissipation path; the bottom of the MOSFET chip is disposed close to the top of the circuit board, the bottom metal sheet is disposed close to the bottom of the circuit board, and the bottom of the MOSFET chip and the bottom metal sheet are thermally connected by the heat-conducting components to form a bottom heat dissipation path; the top metal sheet and the bottom metal sheet are interconnected to form a complete heat dissipation path.

[0009] In some embodiments, the top metal sheet and the top heat dissipation window of the MOSFET chip are configured to maximize their contact area; the gap between the top metal sheet and the top heat dissipation window of the MOSFET chip is filled with a thermally conductive adhesive layer to further improve thermal conductivity.

[0010] In some embodiments, the top metal sheet is a bent metal sheet, including a top wall and a bent portion that bends from one or more sides of the top wall toward the bottom; the top wall is precisely fitted to the top heat dissipation window of the MOSFET chip; the bent portion is connected to the bottom metal sheet.

[0011] In some embodiments, the circuit board has one or more through slots that are adapted to the bending portion, and the end of the bending portion after passing through the slot is connected to the bottom metal sheet.

[0012] In some embodiments, the bent portion of the top metal sheet is connected to the bottom metal sheet by solder through a slot in the circuit board; the bent portion and the bottom metal sheet are interlocked.

[0013] In some embodiments, a slot is provided on the bottom metal sheet, and the end of the bent portion is inserted into the slot; the pins of the MOSFET are connected to the circuit board by solder.

[0014] In some embodiments, the circuit board has a top metal layer on top and a bottom metal layer on the bottom, with the top metal layer and the bottom metal layer forming an intermediate layer of the circuit board; the MOSFET chip is attached to the top metal layer; the bottom metal sheet is attached to the bottom metal layer; the circuit board has one or more vias; the upper and lower ends of the vias are respectively connected to the top metal layer and the bottom metal layer; the heat-conducting component is disposed in the via and connected to the top metal layer and the bottom metal layer to achieve heat transfer.

[0015] In some embodiments, the heat-conducting component is a copper-filled via, which connects the top metal layer and the bottom metal layer.

[0016] In some embodiments, the bottom metal sheet is connected to the circuit board by solder; the MOSFET heat dissipation structure is used in high-current MOSFET or high-power MOSFET applications.

[0017] This application also provides a circuit board on which electronic components are carried, and the circuit board is provided with the MOSFET heat dissipation structure described in any of the above embodiments.

[0018] The beneficial effects of this application are:

[0019] The MOSFET heat dissipation structure of this application uses a dual-path (top heat dissipation path + bottom heat dissipation path) optimized heat dissipation structure to quickly dissipate heat, reduce MOSFET temperature rise, and thus improve heat dissipation efficiency; the optimized heat dissipation allows higher current to pass through, thus enhancing overcurrent capability.

[0020] Furthermore, the MOSFET heat dissipation structure of this application is simple and easy to implement: it fully complies with existing circuit board design and manufacturing processes, has low cost, and is suitable for mass production. Attached Figure Description

[0021] Figure 1 This is a perspective view of the MOSFET chip of this application.

[0022] Figure 2 This is a perspective view of a MOSFET heat sink according to an embodiment of this application.

[0023] Figure 3 This is a schematic diagram of the vias and slots provided on the circuit board according to an embodiment of this application.

[0024] Figure 4 This is a schematic diagram of the MOSFET heat dissipation structure according to an embodiment of this application. Detailed Implementation

[0025] Exemplary embodiments of this application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0026] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "above," "below," "top," "bottom," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, in addition to those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0027] Referring to Figures 1-4, this application provides a high-efficiency heat dissipation structure for MOSFETs. By optimizing the heat dissipation path and increasing the heat dissipation area, the heat dissipation efficiency and overcurrent capability of the MOSFET are significantly improved, ensuring its stability and reliability in high-power applications. The MOSFET heat dissipation structure 100 of this application includes a MOSFET chip 10 and a metal sheet assembly 20 disposed on a circuit board 30. The pins of the MOSFET chip 10 are electrically connected to the circuit board 30. The MOSFET chip 10 has a chip package structure with a top heat dissipation window 12, and the bottom of the chip is attached to the top metal layer 34 on the upper surface of the circuit board 30. The metal sheet assembly 20 serves as the main heat dissipation component, including a top bent metal sheet 21 and a bottom metal sheet 22. The MOSFET chip 10 and the circuit board 30 are sandwiched between the top bent metal sheet 21 and the bottom metal sheet 22. The top bent metal sheet 21 is precisely attached to the top heat dissipation window 12 of the MOSFET chip, forming a direct top heat dissipation path, which can quickly dissipate the heat generated by the MOSFET from the top heat dissipation path. The bottom metal sheet 22 is bonded to the bottom metal layer 35 on the lower surface of the circuit board 30. The top bent metal sheet 21 is interconnected with the bottom metal sheet 22, enabling rapid heat transfer and forming a complete heat dissipation structure. A top metal layer 34 is provided on the upper surface of the circuit board 30, and a bottom metal layer 35 is provided on the lower surface. One or more vias 31 are provided inside the circuit board 30, and a heat-conducting element 40 is provided within each via 31. The heat-conducting element 40 connects the top metal layer 34 and the bottom metal layer 35 of the circuit board to enhance thermal conductivity. The bottom of the chip is bonded to the top metal layer 34 of the circuit board, the bottom metal sheet 22 is bonded to the bottom metal layer 35 of the circuit board, and the heat-conducting element 40 connects the bottom metal layers 34 and 35 on the circuit board, thus forming a bottom heat dissipation path. The top and bottom heat dissipation paths form a complete heat dissipation path. The heat-conducting element 40 can adopt existing heat conduction structures, including but not limited to connectors made of thermally conductive materials such as metal; preferably, the heat-conducting element 40 is a copper-filled via designed inside the circuit board.

[0028] The aforementioned top-path heat dissipation path is configured to maximize the contact area between the top bent metal sheet 21 and the top heat dissipation window 12 of the MOSFET chip, thereby improving heat dissipation efficiency and reducing thermal resistance. As a non-limiting embodiment, the top bent metal sheet 21 includes a top wall 210 and one or more bends 211 bent relative to the top wall 210. The top wall 210 is adapted to and precisely fitted with the top heat dissipation window 12 of the MOSFET chip. For example, the top wall 210 and the top heat dissipation window 12 can be mutually fitted planes or curved surfaces. Further, a thermally conductive adhesive (e.g., thermally conductive grease) is filled into the small gap between the metal sheet 21 and the top heat dissipation window 12 of the MOSFET chip to form a thermally conductive adhesive layer 15, further improving thermal conductivity. The heat generated by the MOSFET chip 10 is rapidly transferred through the chip top heat dissipation window 12, the thermally conductive adhesive layer 15, and the top bent metal sheet 21. The bends 211 allow the top bent metal sheet 21 to fit more closely to the top heat dissipation window 12 of the MOSFET chip and also serve to connect to the bottom metal sheet 22. For example, the bend 211 extends downward relative to the horizontal top wall 210 to form an upright sidewall. The bend 211 is located on the side of the MOSFET chip 10, and the horizontal top wall 210 is in close contact with the top heat dissipation window 12 of the chip. The bend 211 can be formed on one or more sides of the horizontal top wall 210, and a break can be formed between adjacent bends 211 to facilitate the mounting of the top bent metal sheet 21 on the top of the chip 10 and to maximize the contact area with the top heat dissipation window 12. Figure 2 As shown, the bent portion 211 has a T-shaped wall with a narrow end for insertion with the bottom metal sheet 22. The shape and size of the bent metal sheet 21 can be adjusted according to the actual application scenario to ensure its fit with the top heat dissipation window 12 of the MOSFET chip 10.

[0029] The bottom metal sheet 22 is located at the bottom of the circuit board and is fitted to the bottom surface (bottom metal layer 35) of the circuit board. For example, the bottom metal sheet 22 is flat and fits the bottom plane of the circuit board. Furthermore, the bottom metal sheet 22 is connected to the bottom surface of the circuit board by solder and to the bent portion 211 of the top bent metal sheet 21 by solder to further increase the heat dissipation area and heat conduction path. After the metal sheet assembly 20 is mounted on the MOSFET chip 10 and the circuit board 30, the top bent metal sheet 21 is assembled on top of the MOSFET chip 10, with its top wall 210 fitting against the top heat dissipation window 12, and its bent portion 211 extending downwards from the side of the MOSFET chip 10 and connecting to the bottom metal sheet 22. The bottom metal sheet 22 is connected to the circuit board 30 and the bent portion 22 by solder, forming a complete heat dissipation path. A slot 221 is provided on the bottom metal sheet 22. The end of the bent part 211 of the top bent metal sheet 21 is inserted into the slot 221 of the bottom metal sheet 22 and connected to each other. The end of the bent part 211 can be further soldered into the slot 221 by soldering.

[0030] As a non-limiting embodiment, the heat-conducting element 40 can be a directly machined metal cylinder (or sheet, etc.), or it can be a heat-conducting element formed through copper vias in a circuit board. The shape, quantity, and position of the heat-conducting element 40 can be adjusted and configured according to actual needs.

[0031] The circuit board 30 includes a substrate and a MOSFET chip 10 and other electronic components (not shown) mounted on the substrate. As a non-limiting embodiment, the substrate of the circuit board 30 may include a top metal layer 34 (e.g., but not limited to a metal foil) and a bottom metal layer 35 (e.g., but not limited to a metal foil), and an intermediate layer between the two metal layers. The intermediate layer may include one or more substrates, and may also include an intermediate metal layer as needed. The metal layer is typically a copper layer, but is not limited to copper; it may be copper foil or deposited copper. The circuit board 30 substrate is provided with one or more vias 31 (…). Figure 3 The metal layer 31 includes one or more through slots 32. Copper-filled vias are formed within each via 31 as heat-conducting components 40. These vias connect the top metal layer 34 and the bottom metal layer 35, enhancing thermal conductivity and minimizing the heat transfer path, resulting in high heat dissipation efficiency. There can be one or more slots 32, with the bent portion 211 of the top bent metal sheet 21 passing through the slot 32 and connecting to the bottom metal sheet 22.

[0032] In the bottom heat dissipation path, the bottom surface of the MOSFET chip 10 is attached to the top metal layer 34 of the circuit board 30, and the top surface of the bottom metal plate 22 is attached to the bottom metal layer 35 of the circuit board 30. The heat-conducting component (copper via) 40 connects the top metal layer 34 and the bottom metal layer 35 of the MOSFET chip 10 and rapidly transfers heat, thus thermally connecting the bottom of the MOSFET chip 10, which is in close contact with the top metal layer 34, and the bottom metal plate 22, which is in close contact with the bottom metal layer 35. The heat generated by the MOSFET chip 10 / circuit board 30 is rapidly transferred outwards through the heat-conducting component 40 and the bottom metal plate 22. The bottom metal plate 22 is connected to the circuit board 30 and the bent metal plate 21 by solder, forming a complete heat dissipation path. The bent portion 211 of the top bent metal plate 21 extends downwards through the slot 32 and is inserted into the slot 221 of the bottom metal plate 22 for interconnection. In the design of the circuit board 30, the position and number of copper vias 40 are reasonably arranged to ensure that heat can be evenly distributed and quickly dissipated.

[0033] The core of the MOSFET chip 10 is responsible for current control and switching operations. Its package structure includes a top heat dissipation window 12, a surrounding package housing 11, and pins 13 extending from the chip through the package housing 11 and from the sidewalls. The MOSFET pins 13 are connected to the circuit board 30 via solder. The top heat dissipation window 12 of the MOSFET chip is designed to maximize both its area and the contact area with the top bent metal sheet 21. The top heat dissipation window 12 is a heat sink made of heat-transferring material, used to transfer heat from inside the chip to the external heat dissipation structure. In a non-limiting example, the heat dissipation window 12 can be a horizontal recess, a boss, or a plane, etc. Figure 1 and 4 As shown, the heat dissipation window 12 is a shallow recess on the top of the chip 10, with the bottom surface of the recess being a plane with the largest area. The recess is designed to facilitate the filling of the thermally conductive adhesive layer 15. The bottom surface of the MOSFET chip 10 is close to the top surface of the circuit board. For example, the bottom surface of the MOSFET chip 10 is a plane (not limited to a plane), which is in close contact with the top metal layer (e.g., copper foil) 34 of the circuit board 30. The core part of the MOSFET is inside the package structure of the MOSFET chip 10, which is responsible for current control and switching operation. When operating, current flows through it, generating heat. When operating with high current, even more heat is generated, requiring rapid external heat dissipation.

[0034] The circuit board 30 provided in this application carries a MOSFET chip 10 and other electronic components (not shown). The MOSFET chip 10 and other electronic components can be mounted on the circuit board 30 using SMT technology. When assembling the components of the MOSFET heat dissipation structure on the circuit board, the bent metal sheet 21 is first mounted on the MOSFET chip 10, and then the circuit board 30 is connected to the bottom metal sheet 22.

[0035] Specifically, the bent metal plate 21 at the top is installed as follows:

[0036] The bent metal sheet 21 is precisely fitted to the heat dissipation window 12 on the top of the MOSFET to ensure that the contact area between the two is maximized and thermal resistance is reduced.

[0037] A thermally conductive adhesive layer 15 is formed by filling the tiny gap between the bent metal sheet 21 and the heat dissipation window 12 on the top of the MOSFET with thermally conductive adhesive (such as thermally conductive grease) to further improve thermal conductivity.

[0038] Connecting circuit board 30 to bottom metal plate 22 is as follows:

[0039] Pin 13 of MOSFET chip 10 is connected to circuit board 30 by soldering to ensure reliable electrical connection;

[0040] A copper via 40 is designed inside the circuit board 30 to connect the upper and lower copper layers (top metal layer 34 and bottom metal layer 35) to enhance thermal conductivity.

[0041] The bottom metal sheet 22 is connected to the circuit board 30 by solder, and is connected to the bent metal sheet 21 through the slot 32 of the circuit board 30 to form a complete heat dissipation path.

[0042] The MOSFET heat dissipation structure 100 in the above embodiment, through optimized heat dissipation path design, not only improves heat dissipation efficiency but also enhances current carrying capacity, making it suitable for high-power applications. The heat dissipation path optimization includes:

[0043] The bent metal sheet 21 is precisely fitted with the heat dissipation window 12 on the top of the MOSFET chip, forming a direct heat dissipation path, which can quickly dissipate the heat generated by the MOSFET chip.

[0044] By precisely fitting the bent metal sheet 21 to the heat dissipation window 12 on the top of the MOSFET chip, heat can be quickly transferred from the MOSFET chip to the external heat dissipation structure, reducing thermal resistance.

[0045] The pin 13 of the MOSFET chip 10 is connected to the circuit board 30 by solder. The copper via 40 inside the circuit board 30 connects the upper and lower copper layers (top metal layer 34 and bottom metal layer 35) to further enhance the thermal conductivity.

[0046] The copper vias 40 and the bottom metal plate 22 inside the circuit board further increase the heat dissipation area and heat conduction path, ensuring that heat can be quickly dissipated into the surrounding environment.

[0047] The bottom metal plate 22 is connected to the circuit board 30 by solder, and the bent metal plate 21 and the bottom metal plate 22 are connected by solder through the slot 32 of the circuit board to form a complete heat dissipation path, which greatly improves heat dissipation efficiency and current carrying capacity.

[0048] The MOSFET heat dissipation structure of this application has the following advantages:

[0049] 1) High-efficiency heat dissipation: By precisely fitting the bent metal sheet 21 to the heat dissipation window 12 on the top of the MOSFET chip, heat can be quickly transferred from the MOSFET chip to the external heat dissipation structure, reducing thermal resistance; furthermore, the connection between the copper via 40 on the circuit board and the bottom metal sheet 22 increases the heat dissipation area and the heat conduction path, ensuring that heat can be quickly dissipated to the surrounding environment, significantly improving heat dissipation efficiency and ensuring the stable operation of the MOSFET chip in high-power applications.

[0050] 2) Enhanced overcurrent capability: By optimizing the heat dissipation path and increasing the heat dissipation area, this MOSFET heat dissipation structure not only improves heat dissipation efficiency but also enhances overcurrent capability, making it suitable for high-current and high-power applications.

[0051] 3) Simple structure and easy to implement: The MOSFET heat dissipation structure is simple to design, easy to implement in existing circuit board designs, and has low cost, making it suitable for mass production.

[0052] The MOSFET heat dissipation structure of this application significantly reduces thermal resistance, improves heat dissipation efficiency, and enhances overcurrent capability, making it suitable for high-power applications. It is understood that the shape and size of the bent metal sheet can be adjusted according to the actual application scenario to ensure its fit with the heat dissipation window on the top of the MOSFET. In the circuit board design, the location and number of copper vias are rationally arranged to ensure that heat can be evenly distributed and quickly dissipated.

[0053] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A MOSFET heat dissipation structure, comprising a MOSFET chip disposed on a circuit board; characterized in that: The MOSFET heat dissipation structure further includes a metal sheet assembly and one or more heat-conducting components. The metal sheet assembly includes a top metal sheet and a bottom metal sheet. The MOSFET chip has a top heat dissipation window. The top metal sheet and the top heat dissipation window are precisely fitted to form a top heat dissipation path to dissipate the heat generated inside the MOSFET from the top heat dissipation path. The bottom of the MOSFET chip is disposed close to the top of the circuit board, and the bottom metal sheet is disposed close to the bottom of the circuit board. The bottom of the MOSFET chip and the bottom metal sheet are thermally connected by the heat-conducting components to form a bottom heat dissipation path. The top metal sheet and the bottom metal sheet are interconnected to form a complete heat dissipation path.

2. The MOSFET heat dissipation structure as described in claim 1, characterized in that: The top metal plate and the top heat dissipation window of the MOSFET chip are configured to maximize their contact area; the gap between the top metal plate and the top heat dissipation window of the MOSFET chip is filled with a thermally conductive adhesive layer to further improve the thermal conductivity.

3. The MOSFET heat dissipation structure as described in claim 1, characterized in that: The top metal sheet is a bent metal sheet, including a top wall and a bent portion that bends from one or more sides of the top wall toward the bottom; the top wall is precisely fitted to the heat dissipation window on the top of the MOSFET chip; the bent portion is connected to the bottom metal sheet.

4. The MOSFET heat dissipation structure as described in claim 3, characterized in that: The circuit board has one or more through slots that are adapted to the bending portion. After the bending portion passes through the slot, its end is connected to the bottom metal sheet.

5. The MOSFET heat dissipation structure as described in claim 4, characterized in that: The bent portion of the top metal sheet is connected to the bottom metal sheet by solder through a slot in the circuit board; the bent portion and the bottom metal sheet are interlocked.

6. The MOSFET heat dissipation structure as described in claim 5, characterized in that: The bottom metal plate has a slot, and the end of the bent portion is inserted into the slot; the pin of the MOSFET is connected to the circuit board by solder.

7. The MOSFET heat dissipation structure as described in claim 1, characterized in that: The circuit board has a top metal layer on top and a bottom metal layer on the bottom, with an intermediate layer between the top and bottom metal layers; the MOSFET chip is attached to the top metal layer; and the bottom metal sheet is attached to the bottom metal layer. The circuit board is provided with one or more vias; the upper and lower ends of the vias are respectively connected to the top metal layer and the bottom metal layer; the heat-conducting component is disposed in the vias and connected to the top metal layer and the bottom metal layer respectively to realize heat transfer.

8. The MOSFET heat dissipation structure as described in claim 7, characterized in that: The heat-conducting component is a copper-filled via, which connects the top metal layer and the bottom metal layer.

9. The MOSFET heat dissipation structure according to any one of claims 1 to 8, characterized in that: The bottom metal sheet is connected to the circuit board by solder; the MOSFET heat dissipation structure is used for high-current MOSFET or high-power MOSFET applications.

10. A circuit board on which electronic components are mounted, characterized in that: The circuit board is provided with a MOSFET heat dissipation structure as described in any one of claims 1 to 9.

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