Ceramic copper clad plate and preparation method of power module

Abstract

The application provides a preparation method of a ceramic copper-clad plate and a power module. The ceramic copper-clad plate comprises a ceramic layer and a first copper-clad layer and a second copper-clad layer arranged on opposite sides of the ceramic layer. The ceramic copper-clad plate further comprises a protective frame connected with the first copper-clad layer and arranged around the edge of the first copper-clad layer, and the surface of the first copper-clad layer away from the ceramic layer is exposed from the protective frame. The preparation method of the ceramic copper-clad plate and the power module can effectively prevent the molten plastic encapsulating material from flowing to the first copper-clad layer during injection molding, thereby improving the overflow problem and improving the product yield. In addition, the protective frame can also balance the stress to reduce the warping of the ceramic copper-clad plate, thereby improving the flatness of the ceramic copper-clad plate.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a method for fabricating a ceramic copper-clad laminate and a power module. Background Technology

[0002] Ceramic-clad copper (CCL) boards typically have a three-layer structure: the top and bottom layers can be metallic copper, and the middle layer can be an insulating ceramic layer. Based on their manufacturing process, CCL boards can be classified into Direct Bonding Copper (DBC) and Active Metal Brazing (AMB) ceramic substrates. Due to their advantages of high voltage resistance, strong current carrying capacity, and good heat dissipation, CCL boards have become a fundamental material for high-power power electronic circuit structure and interconnection technologies, and are commonly used in power modules for internal circuit layout and chip mounting.

[0003] When ceramic-clad copper (CCL) plates are used in embedded plastic-encapsulated power modules, the underlying copper layer is typically exposed to improve heat dissipation. However, during injection molding, this type of power module is prone to excess molding compound due to the warpage of the CCL and incomplete contact between the CCL and the mold. The molding compound can easily overflow around the exposed underlying copper layer, affecting the module's appearance and performance. Summary of the Invention

[0004] In view of this, this application proposes a ceramic copper-clad laminate that can improve the problem of adhesive overflow and a method for fabricating power modules using the ceramic copper-clad laminate.

[0005] One embodiment of this application provides a ceramic copper-clad laminate, which includes a ceramic layer and a first copper-clad layer and a second copper-clad layer disposed on opposite sides of the ceramic layer. The ceramic copper-clad laminate also includes a protective frame, which is connected to the first copper-clad layer and disposed around the edge of the first copper-clad layer, with the surface of the first copper-clad layer facing away from the ceramic layer exposed from the protective frame.

[0006] In one embodiment, the protective frame includes a sidewall disposed along the edge of the first copper-clad layer, the sidewall having a thickness of 0.5 to 1 mm.

[0007] In one embodiment, the height of the sidewall is 3 to 6 mm along the stacking direction of the ceramic layer and the first copper-clad layer.

[0008] In one embodiment, the protective frame is made of metal.

[0009] In one embodiment, the ceramic layer is made of alumina or aluminum nitride.

[0010] One embodiment of this application provides a method for fabricating a power module, the method comprising the following steps:

[0011] An intermediate to be packaged is provided, the intermediate comprising a ceramic copper-clad laminate as described above and electronic components and pins disposed on the ceramic copper-clad laminate;

[0012] The intermediate is placed in an injection mold, the injection mold including a first mold and a second mold, the first mold having a first groove, the intermediate being placed in the first groove, and the second mold having an injection port;

[0013] Molding compound is injected from the injection port to form a package housing that covers the electronic component, the second copper foil layer, and the ceramic layer. A portion of the pins protrudes from the package housing, and the surface of the first copper-clad laminate facing away from the ceramic layer and the protective frame are exposed from the package housing.

[0014] In one embodiment, the fabrication method further includes: removing the protective frame to form the substrate, and shaping the pins.

[0015] In one embodiment, the bottom portion of the first groove is recessed inward to form a second groove, the second groove being used to accommodate the protective frame.

[0016] In one embodiment, the molding compound includes epoxy resin, alumina, and a thermally conductive filler.

[0017] In one embodiment, the thermally conductive filler material includes aluminum nitride or boron nitride.

[0018] The method for manufacturing the ceramic copper-clad laminate and power module described in this application effectively prevents molten molding compound from flowing into the first copper-clad layer during injection molding by setting a protective frame on the first copper-clad layer. Even if the ceramic copper-clad laminate has warping or gaps, the protective frame can block the molten molding compound outside the frame, allowing it to spread only on the frame. This ensures the complete exposure of the first copper-clad layer, improves the problem of excess adhesive, and increases product yield. Furthermore, the protective frame can also balance stress to reduce warping of the ceramic copper-clad laminate, improving its flatness. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a ceramic copper-clad laminate provided in one embodiment of this application.

[0020] Figure 2 for Figure 1 The image shows a bottom view of the copper-clad ceramic plate.

[0021] Figure 3 for Figure 1 The diagram shows a cross-sectional view of the copper-clad ceramic plate in one embodiment.

[0022] Figure 4 This is a cross-sectional schematic diagram of an intermediate to be packaged according to one embodiment of this application.

[0023] Figure 5 To be Figure 4 The diagram shows a cross-sectional view of the intermediate being placed in an injection mold for injection molding and encapsulation.

[0024] Figure 6 for Figure 5 A cross-sectional view of the first mold of the injection mold shown in one embodiment.

[0025] Figure 7 A schematic diagram of the structure of the injection-molded intermediate in one embodiment.

[0026] Figure 8 for Figure 7 The bottom view of the structure shown.

[0027] Figure 9 This is a schematic diagram of the structure of a power module provided in one embodiment of this application.

[0028] Figure 10 for Figure 9 The diagram shows a cross-sectional view of the power module in one embodiment.

[0029] Explanation of main component symbols

[0030] Ceramic copper clad laminate 100

[0031] Ceramic layer 10

[0032] First copper cladding layer 11

[0033] Second copper cladding layer 12

[0034] Protective frame 20

[0035] Side wall 21

[0036] Copper-clad area 121

[0037] Power Module 1000

[0038] Substrate 101

[0039] Electronic Components 200

[0040] Pin 201

[0041] Encapsulation housing 300

[0042] Intermediate 30

[0043] Injection mold 40

[0044] First mold 41

[0045] Second mold 42

[0046] First groove 411

[0047] Second groove 412

[0048] Injection port 421

[0049] The following detailed description, in conjunction with the accompanying drawings, further illustrates the embodiments of this application. Detailed Implementation

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of this application belong. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application.

[0051] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0052] Embodiments of this application are described herein with reference to cross-sectional views, which are schematic diagrams of idealized embodiments (and intermediate configurations) of this application. Therefore, variations in the shapes illustrated due to manufacturing processes and / or tolerances are foreseeable. Consequently, embodiments of this application should not be construed as limited to the specific shapes of the areas illustrated herein, but should include, for example, deviations in shape due to manufacturing processes. The areas shown in the figures are merely illustrative, and their shapes are not intended to represent the actual shapes of the illustrated devices, nor are they intended to limit the scope of this application.

[0053] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0054] Please see Figures 1 to 3 This application provides a ceramic copper-clad laminate 100, which includes a ceramic layer 10 and a first copper-clad layer 11 and a second copper-clad layer 12 disposed on opposite sides of the ceramic layer 10. The ceramic copper-clad laminate 100 also includes a protective frame 20, which is connected to the first copper-clad layer 11 and is disposed around the edge of the first copper-clad layer 11, with the portion of the first copper-clad layer 11 facing away from the surface of the ceramic layer 10 exposed from the protective frame 20.

[0055] A protective frame 20 is provided on the first copper-clad layer 11, which can effectively prevent molten molding compound (not shown) from flowing onto the surface of the first copper-clad layer 11 away from the ceramic layer 10 during injection molding. Even if the ceramic copper-clad board 100 has warping or gaps, the protective frame 20 can block the molten molding compound outside the protective frame 20, and the molding compound can only spread on the protective frame 20, thereby ensuring the complete exposure of the first copper-clad layer 11 and improving product yield. In addition, the protective frame 20 can also balance stress to reduce warping of the ceramic copper-clad board 100 and improve the flatness of the ceramic copper-clad board 100.

[0056] like Figure 1 and Figure 2 As shown, the ceramic layer 10, the first copper-clad layer 11, and the second copper-clad layer 12 are generally rectangular in shape. Correspondingly, in this embodiment, the protective frame 20 is a generally hollow rectangular frame structure, which is enclosed by four sidewalls 21 arranged along the edge of the first copper-clad layer 11. It can be understood that in other embodiments, if the first copper-clad layer 11 has a different shape, the protective frame 20 is a hollow structure enclosed by several sidewalls 21 arranged around the edge of that shape.

[0057] In some embodiments, the thickness of the sidewall 21 is 0.5–1 mm. Along the stacking direction of the ceramic layer 10 and the first copper-clad laminate 11, the height of the sidewall 21 can be 3–6 mm. This ensures the stability of the protective frame 20, balances the stress of the ceramic copper-clad laminate 100 to reduce warping, and simplifies and simplifies the manufacturing process of the protective frame 20.

[0058] In some embodiments, the protective frame 20 may be made of, but is not limited to, metal. For example, the protective frame 20 may be made of copper (Cu). Making the protective frame 20 of metal not only ensures its stability and balances stress, but also allows it to be easily removed in subsequent operations (e.g., by laser removal).

[0059] In some embodiments, the ceramic layer 10 may be made of insulating ceramic materials such as alumina (Al2O3) or aluminum nitride (AlN), but is not limited to.

[0060] like Figure 1As shown, the second copper clad layer 12 may include a plurality of spaced copper clad areas 121. It is understood that the size of each copper clad area 121 in the second copper clad layer 12 can be determined according to the size of the electronic component, the area required for wire bonding, the area required for terminal soldering, etc. The gap size between adjacent copper clad areas 121 and the distance between the edge of the first copper clad layer 11 or the second copper clad layer 12 and the edge of the ceramic layer 10 can be set according to process requirements and insulation requirements, etc.

[0061] Please see Figures 4 to 10 In another aspect, this application provides a method for fabricating a power module 1000 using the aforementioned ceramic copper-clad laminate 100. The power module 1000 includes a substrate 101, electronic components 200 and pins 201 disposed on the substrate 101, and a package housing 300 covering the substrate 101, the electronic components 200, and the pins 201. The pins 201 can be used to connect to external components (not shown). The power module 1000 may also include bonding wires (not shown) for connecting the various electronic components 200 and pins 201. The method includes the following steps.

[0062] Step S10, please refer to Figure 4 An intermediate 30 to be packaged is provided. The intermediate 30 includes a ceramic copper-clad laminate 100 as described above and electronic components 200 and pins 201 disposed on the ceramic copper-clad laminate 100.

[0063] Specifically, the electronic component 200 and pin 201 are disposed on the surface of the second copper-clad layer 12 of the ceramic copper-clad laminate 100, facing away from the ceramic layer 10. The electronic component 200 may be, but is not limited to, a chip. The chip is disposed on the second copper-clad layer 12 (each copper-clad area 121, see...). Figure 1 The conventional chip mounting methods described in this application can be used on the chip, which will not be elaborated here. The bonding between chips can be achieved through bonding technologies such as wire bonding and clip bonding (also known as clip connection), but not limited to these.

[0064] For step S20, please refer to... Figure 5 The intermediate 30 is placed in the injection mold 40. The injection mold 40 includes a first mold 41 and a second mold 42 adapted to the first mold 41. After the first mold 41 and the second mold 42 are closed, an injection cavity is formed to achieve injection molding encapsulation.

[0065] like Figure 6As shown, the first mold 41 has a first groove 411, which is formed by the inward recess of the surface portion of the first mold 41 near the second mold 42. The intermediate body 30 is placed in the first groove 411. In this embodiment, the first mold 41 is a lower mold, also called a mother mold or stationary mold, and the intermediate body is accommodated by the first groove 411.

[0066] Furthermore, the bottom portion of the first groove 411 is recessed inward to form a second groove 412, which is used to accommodate the protective frame 20 (see reference). Figure 5 ).

[0067] Please see Figure 5 The second mold 42 is provided with an injection port 421, through which molding compound (not shown) is injected into the injection mold 40. In this embodiment, the second mold 42 is the upper mold, also called the male mold or the moving mold. The shape of the second mold 42 is adapted to the shape of the packaging shell 300 so as to form the outer shape of the packaging shell 300 after injection molding.

[0068] For step S30, please refer to the following. Figure 5 Molding material is injected through the injection port 421 to form the encapsulation housing 300. The injection mold 40 is then removed to obtain the desired product. Figure 7 and Figure 8 The intermediate body 30 shown is the injection-molded part.

[0069] In some embodiments, the molding compound includes epoxy resin, alumina, and a thermally conductive filler. Further, the thermally conductive filler may be, but is not limited to, aluminum nitride or boron nitride. Aluminum nitride and boron nitride have good insulation properties, high thermal conductivity, good heat resistance and thermal conductivity, and high heat transfer and dissipation capabilities. When manufacturing the encapsulation housing 300, materials such as epoxy resin, alumina, boron nitride, or aluminum nitride can be mixed, and then the molten molding compound can be injected into the injection port 421 after heating.

[0070] like Figure 5 As shown, the package housing 300 covers the electronic component 200, the second copper-clad layer 12, and the ceramic layer 10. A portion of the pin 201 extends from within the package housing 300. The surface of the first copper-clad layer 11 facing away from the ceramic layer 10 and the protective frame 20 are exposed within the package housing 300. The partial exposure of the first copper-clad layer 11 outside the package housing 300 improves the heat dissipation of the power module 1000. Furthermore, when a heat sink (not shown) is also provided outside the power module 1000, the surface of the first copper-clad layer 11 exposed outside the package housing 300 can better conform to the heat sink, thereby further improving the heat dissipation of the power module 1000.

[0071] like Figure 5 As shown, a protective frame 20 is provided on the first copper-clad layer 11, which can effectively prevent the molten molding compound from flowing to the first copper-clad layer 11 during injection molding. Even if the ceramic copper-clad board 100 has warping or gaps, the protective frame 20 can block the molten molding compound outside the protective frame 20. The molding compound can only spread on the protective frame 20, thereby ensuring the complete exposure of the first copper-clad layer 11 and improving the product yield.

[0072] For step S40, please refer to... Figure 9 and Figure 10 The protective frame 20 is removed to form the substrate 101, and the pins 201 are shaped to obtain the power module 1000.

[0073] Specifically, the protective frame 20 can be removed by means of laser treatment, but not limited to laser removal. After removing the protective frame 20, the ceramic copper-clad laminate 100 forms the substrate 101. Figure 10 As shown, the substrate 101 includes a ceramic layer 10 and a first copper-clad layer 11 and a second copper-clad layer 12 disposed on opposite sides of the ceramic layer 10. The electronic component 200 and the pin 201 are disposed on the surface of the second copper-clad layer 12 of the substrate 101 away from the ceramic layer 10.

[0074] Specifically, the shaping operation of the pin 201 (commonly referred to as "beam cutting" in the art) is a common technical means in the art, and will not be described in detail here.

[0075] The method for manufacturing the ceramic copper-clad laminate 100 and power module 1000 described in this application, by setting a protective frame 20 on the first copper-clad layer 11, can effectively prevent molten molding compound from flowing to the first copper-clad layer 11 during injection molding. Even if the ceramic copper-clad laminate 100 has warping or gaps, the protective frame 20 can also block the molten molding compound outside the protective frame 20, allowing the molding compound to spread only on the protective frame 20, thereby ensuring the complete exposure of the first copper-clad layer 11, improving the problem of excess adhesive, and increasing product yield. Furthermore, the protective frame 20 can also balance stress to reduce warping of the ceramic copper-clad laminate 100, improving the flatness of the ceramic copper-clad laminate 100.

[0076] The above description describes some specific embodiments of this application, but in actual applications, the application should not be limited to these embodiments. For those skilled in the art, other modifications and alterations made based on the technical concept of this application should fall within the protection scope of this application.

Claims

1. A method for fabricating a power module, characterized in that, The preparation method includes the following steps: An intermediate to be packaged is provided, the intermediate including a ceramic copper-clad laminate and electronic components and pins disposed on the ceramic copper-clad laminate; wherein, the ceramic copper-clad laminate includes a ceramic layer and a first copper-clad layer and a second copper-clad layer disposed on opposite sides of the ceramic layer, the ceramic copper-clad laminate also includes a removable protective frame, the protective frame being connected to the first copper-clad layer and disposed around the edge of the first copper-clad layer, the surface of the first copper-clad layer facing away from the ceramic layer being exposed from the protective frame; The intermediate is placed in an injection mold, the injection mold including a first mold and a second mold, the first mold having a first groove, the intermediate being placed in the first groove, and the second mold having an injection port; Molding material is injected from the injection port to form a package housing, which covers the electronic component, the second copper layer of the ceramic copper-clad laminate, and the ceramic layer. A portion of the pins protrudes from the package housing, and the first copper layer of the ceramic copper-clad laminate is exposed from the surface of the ceramic layer and the protective frame. Remove the protective frame and shape the pins.

2. The method for preparing the power module as described in claim 1, characterized in that, The bottom portion of the first groove is recessed inward to form a second groove, which is used to accommodate the protective frame.

3. The method for preparing the power module as described in claim 1, characterized in that, The molding compound includes epoxy resin, alumina, and thermally conductive filler.

4. The method for preparing the power module as described in claim 3, characterized in that, The thermally conductive filler material includes aluminum nitride or boron nitride.

5. The method for preparing the power module as described in claim 1, characterized in that, The protective frame includes a sidewall disposed along the edge of the first copper-clad layer, the sidewall having a thickness of 0.5 to 1 mm.

6. The method for preparing the power module as described in claim 1, characterized in that, The protective frame includes a sidewall disposed along the edge of the first copper-clad layer, and the height of the sidewall is 3-6 mm along the stacking direction of the ceramic layer and the first copper-clad layer.

7. The method for preparing the power module as described in claim 1, characterized in that, The protective frame is made of metal.

8. The method for preparing the power module as described in claim 1, characterized in that, The ceramic layer is made of either alumina or aluminum nitride.

Images