A power module with a novel structure directly using a radiator as a shell and its preparation method

Abstract

The present invention relates to the field of electronic technology, and specifically provides a power module with a novel structure directly using a heat sink as a shell and a preparation method thereof, comprising: a heat sink body, the heat sink body being provided with a groove; a copper-clad ceramic substrate being flatly fixed to the bottom of the groove, the copper-clad ceramic substrate being connected to the heat sink via a thermally conductive solder, and the copper-clad ceramic substrate being provided with a chip and a signal transmission terminal; a silicone protective layer formed by silicone being filled in the groove, the signal transmission terminal extending through the silicone protective layer to be connected to an external application end, the heat sink body being a metal heat sink, and the heat sink body being provided with heat dissipation fins; the power module of the present invention has high heat dissipation efficiency between the power module and the heat sink body; when the power module fails and explodes, the ejection direction of the failed object can be controlled to avoid damage to other components in the entire machine.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to a power module directly using a radiator as a shell and a preparation method of the power module. Background Art

[0002] The structure of a conventional power module is that the chip is welded to a copper-clad ceramic substrate, which is then welded to a copper base plate. The semi-finished copper base plate formed after welding is then bonded to a plastic shell using silicone, and then filled with insulating silicone for protection. During use of the power module, thermal grease is first applied to the back of the copper base plate. The power module is then mounted on the heat sink body by applying pressure by tightening screws. The thermal grease then fills the gap between the copper base plate and the heat sink body. Because conventional power modules have plastic shells, they have poor heat dissipation performance. In addition, the heat dissipation of power devices in the prior art is achieved through thermal grease, which has a relatively low heat dissipation coefficient and affects the heat dissipation of the power module. Furthermore, the hardness of engineering plastics is relatively low and cannot provide sufficient protection. When the power module fails and explodes, it will spray failed materials in all directions, causing damage to surrounding components. Summary of the Invention

[0003] The purpose of the present invention is to provide a power module with a novel structure that directly uses a heat sink as a shell to solve the above technical problems;

[0004] The present invention also aims to provide a method for preparing a power module to solve the above technical problems;

[0005] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0006] A power module with a novel structure directly using a heat sink as a shell includes:

[0007] A radiator body, wherein a groove is formed on the radiator body;

[0008] A copper-clad ceramic substrate is flatly fixed on the bottom of the groove, the copper-clad ceramic substrate is connected to the heat sink via a thermally conductive solder, and a chip and a signal transmission terminal are provided on the copper-clad ceramic substrate;

[0009] The groove is filled with a silicone protective layer formed by silicone, and the signal transmission terminal extends out of the silicone protective layer to connect to an external application end.

[0010] Preferably, the radiator body is made of metal, and heat dissipation fins are provided on the radiator body.

[0011] Preferably, the heat dissipation fins include a plurality of heat dissipation metal sheets parallel to each other, and the distances between the heat dissipation metal sheets are the same.

[0012] Preferably, the silicone protective layer and the groove form a protective chamber that limits the ejection direction of the failure object, the bottom and surrounding areas of the protective chamber are metal surfaces, and the top of the protective chamber is a silicone surface.

[0013] Preferably, the back side of the chip is fixed on the copper-clad ceramic substrate, and the functional lead-out terminals on the front side of the chip are connected to the copper-clad ceramic substrate via wires.

[0014] Preferably, the lead wire is an aluminum wire.

[0015] Preferably, a copper foil area is provided on the copper-clad ceramic substrate, and the signal transmission terminal is welded to the copper foil area.

[0016] Preferably, the silicone protective layer is filled in the groove and covers the copper-clad ceramic substrate.

[0017] Preferably, the thermally conductive solder is a metal thermally conductive solder.

[0018] A method for preparing a power module, applied to the power module, comprising:

[0019] Step S1, soldering the chip onto the copper-clad ceramic substrate;

[0020] Step S2, connecting the functional lead-out terminals on the front side of the chip to the copper-clad ceramic substrate via leads;

[0021] Step S3, welding the signal transmission terminal to the copper foil area on the copper-clad ceramic substrate;

[0022] Step S4, welding the copper-clad ceramic substrate to the bottom of the groove through the thermally conductive solder to achieve connection with the radiator body;

[0023] Step S5: pouring silica gel into the groove to form the silica gel protective layer.

[0024] The beneficial effects of the present invention are as follows: due to the adoption of the above technical solution, the heat dissipation efficiency between the power module and the radiator body of the present invention is high; when the power module fails and explodes, the ejection direction of the failed object can be controlled to avoid damage to the components outside the power module. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of the power module in an embodiment of the present invention;

[0026] Figure 2 is a cross-sectional view of a power module according to an embodiment of the present invention;

[0027] Figure 3 Schematic diagram of the steps of a method for preparing a power module in an embodiment of the present invention.

[0028] In the accompanying drawings: 1. radiator; 11. groove; 12. heat dissipation fins; 121. heat dissipation metal sheet; 2. copper-clad ceramic substrate; 3. chip; 4. signal transmission terminal; 5. silicone protective layer; 6. lead. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0032] A new type of power module with a heat sink as the shell. Figure 1 as well as Figure 2 As shown, including:

[0033] The radiator body 1 is provided with a groove 11;

[0034] The copper-clad ceramic substrate 2 is flatly fixed on the bottom of the groove 11. The copper-clad ceramic substrate 2 is connected to the heat sink 1 through a thermally conductive solder. The copper-clad ceramic substrate 2 is provided with a chip 3 and a signal transmission terminal 4.

[0035] A silicone protective layer 5 formed of silicone is filled in the groove 11 , and the signal transmission terminal 4 extends out of the silicone protective layer 5 to connect to an external application end.

[0036] In a preferred embodiment, the radiator body 1 is made of metal, and heat dissipation fins 12 are provided on the radiator body 1; specifically, the heat dissipation fins 12 include a plurality of heat dissipation metal fins 121 parallel to each other, and the spacing between the heat dissipation metal fins 121 is the same.

[0037] In a preferred embodiment, the silicone protective layer 5 and the groove 11 form a protective chamber that limits the ejection direction of the failure object. The bottom and surrounding areas of the protective chamber are metal surfaces, and the top of the protective chamber is a silicone surface.

[0038] Specifically, the present invention directly uses the radiator body 1 as the shell of the power module, thereby achieving better heat dissipation efficiency. By opening a groove 11 in the radiator body 1, the copper-clad ceramic substrate 2 welded with the chip 3 and the signal transmission terminal 4 is welded to the bottom of the groove 11 of the radiator body 1 to achieve connection with the radiator body 1; the silicone protective layer 5 is used to solve the safety hazard of spraying failure objects when the power module fails.

[0039] In a preferred embodiment, the back side of the chip 3 is fixed on the copper-clad ceramic substrate 2, and the functional lead-out terminal on the front side of the chip 3 is connected to the copper-clad ceramic substrate 2 via a lead 6. Specifically, the lead 6 is an aluminum wire.

[0040] Specifically, the present invention utilizes the principle of ultrasonic cold brazing to connect the front surface of the chip 3 and the copper-clad ceramic substrate 2 to the same potential through an aluminum wire, thereby interconnecting the front surface of the chip 3 and the copper-clad ceramic substrate 2. Moreover, the aluminum wire can freely connect the parts of the copper-clad ceramic substrate 2 circuit that require an equipotential connection, thereby realizing the function of a free jumper, thereby leading out the various functional ends of the chip 3.

[0041] In a preferred embodiment, a copper foil area is provided on the copper-clad ceramic substrate 2, and the signal transmission terminal 4 is welded to the copper foil area, specifically, welded to the copper foil area on the DBC board. The functional ends of the chip 3 are directly interconnected with it through the copper foil or through aluminum wire jumpers, and then led out to the application end for connection and use.

[0042] In a preferred embodiment, the silicone protective layer 5 is filled in the groove 11 and covered on the copper-clad ceramic substrate 2. Once the power module fails and explodes, the spray direction of the failed material can be controlled to avoid damage to other components in the entire machine. Specifically, because the groove 11 of the radiator body 1 has a structural feature that the bottom and the four sides are metal surfaces, and only the top is an empty surface, silicone can be poured from above the copper-clad ceramic substrate 2 to form a silicone protective layer 5 that insulates air. Furthermore, since the top is a silicone surface and the other surfaces are metal surfaces, the hardness of the silicone surface directly above is the lowest. When an explosion occurs, the ejecta will be ejected from the weak point, that is, directly above, thereby achieving controllable fault spray direction. It should be noted that no components are arranged at the corresponding spray surface of the external application module.

[0043] In a preferred embodiment, the thermal conductive solder is a metal thermal conductive solder; preferably, SnAgCu solder is used, and the thermal conductive solder replaces the thermal conductive silicone grease to connect the radiator body 1 and the copper-clad ceramic substrate 2. Since the thermal conductivity of the thermal conductive solder is much greater than that of the thermal conductive silicone grease, usually about 15 to 20 times, the power module obtains significant heat dissipation benefits compared with the existing technology.

[0044] A method for preparing a power module is applied to the power module in any embodiment, such as Figure 3 Shown, including:

[0045] Step S1, soldering the chip 3 to the copper-clad ceramic substrate 2;

[0046] Step S2, connecting the functional lead-out terminals on the front side of the chip 3 to the copper-clad ceramic substrate 2 via the leads 6;

[0047] Step S3, welding the signal transmission terminal 4 to the copper foil area on the copper-clad ceramic substrate 2;

[0048] Step S4, soldering the copper-clad ceramic substrate 2 to the bottom of the groove 11 through a thermally conductive solder to achieve connection with the radiator body 1;

[0049] In step S5, silicone is poured into the groove 11 to form a silicone protective layer 5. The above description is only a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should be able to realize that any equivalent substitution and obvious changes made by using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A power module with a novel structure that directly uses a heat sink as a shell, characterized in that: include: A radiator body, wherein a groove is formed on the radiator body; A copper-clad ceramic substrate is flatly fixed on the bottom of the groove, the copper-clad ceramic substrate is connected to the heat sink via a thermally conductive solder, and a chip and a signal transmission terminal are provided on the copper-clad ceramic substrate; The groove is filled with a silicone protective layer formed by silicone, and the signal transmission terminal extends out of the silicone protective layer to connect to the external application end; The radiator body is made of metal; The silicone protective layer and the groove form a protective chamber that limits the ejection direction of the failure object; The external application module has no components arranged on the side corresponding to the ejection direction of the failure object.

2. The power module according to claim 1, wherein: The radiator body is also provided with heat dissipation fins.

3. The power module according to claim 2, wherein: The heat dissipation fins include a plurality of heat dissipation metal sheets parallel to each other, and the distances between the heat dissipation metal sheets are the same.

4. The power module according to claim 2, wherein: The bottom and surrounding areas of the protection chamber are metal surfaces, and the top of the protection chamber is a silicone surface.

5. The power module according to claim 1, wherein: The back side of the chip is fixed on the copper-clad ceramic substrate, and the functional lead-out terminals on the front side of the chip are connected to the copper-clad ceramic substrate via leads.

6. The power module according to claim 5, characterized in that: The lead wire is an aluminum wire.

7. The power module according to claim 1, wherein: A copper foil area is provided on the copper-clad ceramic substrate, and the signal transmission terminal is welded to the copper foil area.

8. The power module according to claim 1, wherein: The silicone protective layer is filled in the groove and covers the copper-clad ceramic substrate.

9. The power module according to claim 1, wherein: The heat-conducting solder is a metal heat-conducting solder.

10. A method for preparing a power module, applied to the power module according to any one of claims 1 to 9, characterized in that: include: Step S1, soldering the chip onto the copper-clad ceramic substrate; Step S2, connecting the functional lead-out terminals on the front side of the chip to the copper-clad ceramic substrate via leads; Step S3, welding the signal transmission terminal to the copper foil area on the copper-clad ceramic substrate; Step S4, welding the copper-clad ceramic substrate to the bottom of the groove through the thermally conductive solder to achieve connection with the radiator body; Step S5: pouring silica gel into the groove to form the silica gel protective layer.

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