Power module packaging structure and power module

Abstract

The embodiment of the invention provides a power module packaging structure and a power module, the structure comprises a carrier plate, a plurality of metal bottom plates, a plurality of substrates, a plurality of chips, a plurality of external terminals and a plastic package body, and the edge area of the carrier plate is provided with a plurality of through holes penetrating through the thickness of the carrier plate; the metal bottom plate is arranged on the upper surface of the carrier plate; the substrate is arranged on the metal bottom plate corresponding to the substrate; the chip is arranged on the substrate corresponding to the chip; the first end of the external terminal is fixed on the substrate and is electrically connected with the chip; the plastic package body is arranged on the upper surface of the carrier plate, fills the through hole and wraps the metal bottom plate, the substrate, the chip and part of the external terminal, and the second end of the external terminal penetrates out of the plastic package body. According to the structure, the substrate and the metal bottom plate are arranged on the carrier plate in a small packaging unit mode, CTE difference can be localized, overall stress accumulation is avoided, CTE mismatch is relieved, and reliability is improved; the through hole is filled with the plastic package body, so that the bonding strength of the plastic package body and the carrier plate is improved, and stripping of the plastic package body and the carrier plate is prevented.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the field of semiconductor packaging technology, and particularly relate to a power module packaging structure and a power module. Background Art

[0002] A power module is a module that integrates power devices according to a certain functional combination. Compared with discrete devices, its structure shortens the current loop and reduces conduction loss.

[0003] like Figure 1 and Figure 2 As shown, the specific packaging process of the existing power module is as follows: several substrates 1 are fixed on the frame 3 through pins 2, the power device 4 is fixed to the surface of the substrate 1 by welding, and signal transmission is achieved through wire bonding 5 and pins 6. After the EMC 7 protection device is formed, the pins 2 are cut off to separate the frame 3 and the substrate 1 to complete the module packaging, and finally the substrate 1 is welded to the metal base plate to achieve heat dissipation.

[0004] The existing power module packaging process has the following problems:

[0005] 1) Due to the limitation of frame size, the number of power modules that can be integrated on the frame is limited, and the packaging efficiency is low;

[0006] 2) The large-size substrate exacerbates the CTE mismatch problem between the substrate, EMC and metal base plate, affecting the reliability of the power module.

[0007] In view of the above problems, it is necessary to propose a power module packaging structure and a power module that are reasonably designed and effectively solve the above problems. Summary of the Invention

[0008] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a power module packaging structure and a power module.

[0009] An aspect of an embodiment of the present disclosure provides a power module packaging structure, including:

[0010] A carrier plate, wherein the edge region of the carrier plate is provided with a plurality of through holes extending through the thickness of the carrier plate;

[0011] A plurality of metal base plates, wherein the plurality of metal base plates are disposed on the upper surface of the carrier plate;

[0012] A plurality of substrates, each of which is disposed on the corresponding metal base plate;

[0013] A plurality of chips, each of which is disposed on the corresponding substrate;

[0014] a plurality of external terminals, wherein first ends of the external terminals are fixed to the substrate and electrically connected to the chip;

[0015] A plastic package body is provided on the upper surface of the carrier board and fills the through hole, and wraps the metal bottom plate, the substrate, the chip and part of the external terminals, wherein the second end of the external terminal passes through the plastic package body.

[0016] Optionally, a plurality of blind holes are provided on the lower surface of the carrier plate.

[0017] Optionally, the plurality of blind holes are evenly distributed on the lower surface of the carrier board.

[0018] Optionally, the plurality of blind holes are evenly distributed in the edge area of ​​the lower surface of the carrier board and are located inside the through hole.

[0019] Optionally, the blind hole is an arc blind hole.

[0020] Optionally, a plurality of the through holes are arranged at equal intervals in the edge area of ​​the carrier board.

[0021] Optionally, the packaging structure further includes a temporary bonding adhesive layer;

[0022] The temporary bonding adhesive layer is arranged between the carrier board and the plurality of metal base plates.

[0023] Optionally, the packaging structure further includes bonding wires;

[0024] The bonding wires are respectively electrically connected between the chip and the corresponding substrate, and between two adjacent chips.

[0025] Optionally, the carrier plate is made of a material that matches the CTE of the metal base plate.

[0026] Another aspect of the present disclosure provides a power module, which is obtained by cutting the power module packaging structure described above after removing the carrier board, and includes:

[0027] at least one metal base plate;

[0028] At least one substrate, the substrate being disposed on the corresponding metal base plate;

[0029] at least one chip, wherein the chip is disposed on the corresponding substrate;

[0030] at least one external terminal, a first end of the external terminal being fixed to the substrate and electrically connected to the chip;

[0031] A plastic package body encapsulates the metal bottom plate, the substrate, the chip and part of the external terminals, wherein the second ends of the external terminals pass through the plastic package body.

[0032] The power module packaging structure and power module of the embodiments of the present disclosure are characterized in that a plurality of small-sized metal base plates are arranged on the upper surface of a large-sized carrier plate, and a plurality of substrates are arranged on the corresponding metal base plates to form a plurality of array-type packaging small units, breaking through the frame size limitation in the prior art, realizing batch packaging, and greatly improving the packaging efficiency; the substrates and the metal base plates are arranged on the carrier plate in the form of array-type packaging small units, localizing the CTE difference between the substrate, the plastic package body and the metal base plate, avoiding overall stress accumulation, alleviating CTE mismatch, and improving the reliability of the power module packaging structure; a plurality of through holes are provided in the edge area of ​​the carrier plate, and the through holes are filled with the plastic package body to form an anchoring structure, thereby improving the bonding strength between the plastic package body and the carrier plate, specifically alleviating the shear stress at the edge of the plastic package body, preventing the plastic package body from peeling off from the carrier plate, and further improving the reliability of the power module. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 and Figure 2 A schematic diagram of a power module packaging process in the prior art;

[0034] Figure 3 This is a schematic structural diagram of a power module packaging structure according to one embodiment of the present disclosure;

[0035] Figure 4 This is a schematic structural diagram of a power module packaging structure according to another embodiment of the present disclosure;

[0036] Figure 5 This is a schematic structural diagram of a power module packaging structure according to another embodiment of the present disclosure;

[0037] Figure 6 This is a schematic structural diagram of multiple through holes in another embodiment of the present disclosure;

[0038] Figure 7 This is a schematic structural diagram of multiple through holes in another embodiment of the present disclosure;

[0039] Figure 8 This is a schematic structural diagram of a power module according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solutions of the embodiments of the present disclosure, the embodiments of the present disclosure are further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0041] like Figures 3 to 5 As shown, an embodiment of the present disclosure provides a power module packaging structure, including a carrier 100 , a plurality of metal base plates 102 , a plurality of substrates 104 , a plurality of chips 110 , a plurality of external terminals 112 and a plastic package 113 .

[0042] The carrier board 100 has an upper surface and a lower surface along its thickness. A plurality of through-holes 1001 extending through the thickness of the carrier board 100 are provided at the edge of the carrier board 100. Specifically, the plurality of through-holes 1001 extending through the thickness of the carrier board 100 can be formed at the edge of the carrier board 100 by machining (e.g., stamping) or laser drilling.

[0043] A plurality of metal base plates 102 are disposed on the upper surface of the carrier 100 .

[0044] The plurality of substrates 104 are disposed on the corresponding metal base plate 102. In other words, the substrates 104 correspond one to one with the metal base plate 102. The metal base plate 102 can serve as heat dissipation and structural support for the substrates 104.

[0045] The plurality of chips 110 are disposed on the corresponding substrates 104. Specifically, in this embodiment, the plurality of chips 110 are fixed on the corresponding substrates 104 by solder / silver paste bonding.

[0046] First ends of the plurality of external terminals 112 are fixed to the substrate 104 and electrically connected to the chip 110 to lead out signals from the chip 110 .

[0047] Specifically, the first ends of the plurality of external terminals 112 can be fixed to the pads of the substrate 104 by reflow soldering, and then the external terminals 112 are electrically connected to the chip 110 via bonding wires 111 to lead out the signals of the chip 110. Alternatively, the first ends of the plurality of external terminals 112 can be fixed to the pin holders of the substrate 104 by mechanical pressing, and then the external terminals 112 are electrically connected to the chip 110 via bonding wires 111 to lead out the signals of the chip 110. It should be noted that in this embodiment, the external terminals 112 can be pins.

[0048] Plastic encapsulation 113 is disposed on the upper surface of carrier 100 and fills through-holes 1001. It also encapsulates metal base plate 102, substrate 104, chip 110, and a portion of external terminals 112. The second ends of external terminals 112 extend beyond plastic encapsulation 113. Plastic encapsulation 113 protects metal base plate 102, substrate 104, chip 110, and a portion of external terminals 112. Filling through-holes 1001 with plastic encapsulation 113 enhances the bonding strength between plastic encapsulation 113 and carrier 100, specifically alleviating shear stress at the edges of plastic encapsulation 113 and preventing separation of plastic encapsulation 113 from carrier 100.

[0049] The power module packaging structure and power module of the embodiments of the present disclosure are characterized in that a plurality of small-sized metal base plates are arranged on the upper surface of a large-sized carrier plate, and a plurality of substrates are arranged on the corresponding metal base plates to form a plurality of array-type packaging small units, breaking through the frame size limitation in the prior art, realizing batch packaging, and greatly improving the packaging efficiency; the substrates and the metal base plates are arranged on the carrier plate in the form of array-type packaging small units, localizing the CTE difference between the substrate, the plastic package body and the metal base plate, avoiding overall stress accumulation, alleviating CTE mismatch, and improving the reliability of the power module packaging structure; a plurality of through holes are provided in the edge area of ​​the carrier plate, and the through holes are filled with the plastic package body to form an anchoring structure, thereby improving the bonding strength between the plastic package body and the carrier plate, specifically alleviating the shear stress at the edge of the plastic package body, preventing the plastic package body from peeling off from the carrier plate, and further improving the reliability of the power module.

[0050] For example, Figure 4 and Figure 5 As shown, a plurality of blind holes 100 a are provided on the lower surface of the carrier board 100 .

[0051] like Figure 4 As shown in FIG. 1 , in one embodiment, a plurality of blind holes 100a can be evenly distributed on the lower surface of the carrier 100 and located inside the through hole 1001. Figure 5 As shown, in another embodiment, the plurality of blind holes 100 a may also be evenly distributed on the edge area of ​​the lower surface of the carrier 100 and located inside the through hole 1001 .

[0052] It should be noted that the number and distribution positions of the blind holes 100 a are not specifically limited in this embodiment and can be limited according to actual needs.

[0053] In this embodiment, by forming multiple blind holes on the lower surface of the carrier, when a plastic package is set on the upper surface of the carrier, the shrinkage stress of the plastic package during curing can be absorbed and dispersed, preventing the edge of the plastic package from warping up and balancing the stress distribution on the upper and lower surfaces of the carrier.

[0054] For example, in this embodiment, the blind holes 100a are arc blind holes. A plurality of arc blind holes 100a can be formed on the lower surface of the carrier 100 by machining (such as stamping) or laser etching.

[0055] For example, Figure 6 and Figure 7 As shown, in this embodiment, a plurality of through holes 1001 are evenly spaced at the edge of the carrier 100. The plastic encapsulation body 113 is filled in the evenly spaced through holes 1001, which can better enhance the bonding strength between the plastic encapsulation body 113 and the carrier 100 and specifically alleviate the edge shear stress of the plastic encapsulation body 113.

[0056] Specifically, if Figure 6As shown, a row of through holes 1001 can be formed in each edge region of the carrier 100 in the longitudinal direction. Figure 7 As shown, a row of through holes 1001 may also be formed on each side of the carrier board 100. The number, size, and distribution of the through holes 1001 are not specifically limited in this embodiment and may be selected according to actual needs.

[0057] For example, Figures 3 to 5 As shown, the package structure further includes a temporary bonding layer 101, which is disposed between the carrier 100 and a plurality of metal base plates 102. Specifically, the plurality of metal base plates 102 are fixed to the carrier 100 via the temporary bonding layer 101. The temporary bonding layer 101 can be disposed on the carrier 100 by spin coating, lamination, or other methods.

[0058] For example, Figures 3 to 5 As shown, the package structure further includes bonding wires 111, which are electrically connected between the chip 110 and the corresponding substrate 104, and between two adjacent chips 110. The bonding wires 111 can realize electrical connection between the chip 110 and the substrate 104, and can realize electrical connection between two adjacent chips 110.

[0059] In this embodiment, substrate 104 can be a DBC (copper-clad ceramic substrate) or an AMB (active metal brazing substrate), among others. Substrate 104 includes an insulating layer and a metal layer. The metal layers are disposed on the upper and lower surfaces of the insulating layer, respectively. It should be noted that this embodiment does not impose any specific restrictions on the type of substrate 104 and can be selected based on actual needs.

[0060] For example, in this embodiment, the carrier 100 is made of a material that matches the CTE of the metal base plate 102 to reduce thermal stress. For example, in this embodiment, the carrier 100 can be made of stainless steel, and the metal base plate 102 can be made of aluminum or copper.

[0061] For example, in this embodiment, Figures 3 to 5 As shown, the package structure further includes a solder layer 103, which is disposed between the substrate 104 and the metal bottom plate 102. The substrate 104 is fixed to the corresponding metal bottom plate 102 by soldering through the solder layer 103.

[0062] like Figure 8 As shown, another aspect of the embodiment of the present disclosure provides a power module 200, Figures 3 to 5 The power module packaging structure is obtained by cutting after removing the carrier board. The specific structural features of the power module packaging structure have been described in detail above and will not be repeated here.

[0063] The specific process of removing the carrier 100 can be as follows: first, decompose the temporary bonding adhesive layer 101 to separate the carrier 100. Specifically, since the carrier 100 is made of metal and is opaque, the laser can be used to scan the adhesive layer interface of the temporary bonding adhesive layer 101, and the laser decomposes the temporary bonding adhesive layer 101 and then peels off the carrier 100. Then, the residual temporary bonding adhesive layer 101 is cleaned and removed. In this embodiment, the peeled carrier 100 can be recycled to save costs. After removing the carrier 100, the plastic package 113 between the two adjacent metal base plates 102 is cut to obtain Figure 8 A plurality of individual power modules 200 are shown.

[0064] Specifically, if Figure 8 As shown, the power module 200 includes at least one metal base plate 102, at least one substrate 104, at least one chip 110, at least one external terminal 112, and a plastic package 113. The number of metal base plates 102, substrates 104, chips 110, and external terminals 112 is not specifically limited in this embodiment and can be selected based on actual needs.

[0065] The substrate 104 is disposed on the corresponding metal base plate 102 , wherein the substrate 104 is fixed to the metal base plate 102 via the solder layer 103 .

[0066] The chip 110 is disposed on the corresponding substrate 104 .

[0067] A first end of the external terminal 112 is disposed on the substrate 104 and electrically connected to the chip 110 through the bonding wire 111 to lead out a signal from the chip 110 .

[0068] The plastic package 113 wraps the metal base plate 102 , the substrate 104 , the chip 110 and part of the external terminals 112 , wherein the second ends of the external terminals 112 pass through the plastic package 113 to lead out the signals of the chip 110 .

[0069] In the power module of the disclosed embodiment, each substrate is arranged on a corresponding metal base plate to form a plurality of array-type packaged small units, which can reduce the interface stress concentration problem caused by the CTE mismatch of the materials and improve the reliability of the power module; in addition, the substrate corresponds one-to-one with the metal base plate, thereby enhancing the heat dissipation and mechanical support of the substrate.

[0070] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the embodiments of the present disclosure, but the embodiments of the present disclosure are not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and essence of the embodiments of the present disclosure, and such modifications and improvements are also considered to be within the scope of protection of the embodiments of the present disclosure.

Claims

1. A power module packaging structure, characterized in that: include: A carrier plate, wherein the edge region of the carrier plate is provided with a plurality of through holes extending through the thickness of the carrier plate; A plurality of metal base plates, wherein the plurality of metal base plates are disposed on the upper surface of the carrier plate; A plurality of substrates, each of which is disposed on the corresponding metal base plate; A plurality of chips, each of which is disposed on the corresponding substrate; a plurality of external terminals, wherein first ends of the external terminals are fixed to the substrate and electrically connected to the chip; A plastic package body is provided on the upper surface of the carrier board and fills the through hole, and wraps the metal bottom plate, the substrate, the chip and part of the external terminals, wherein the second end of the external terminal passes through the plastic package body.

2. The packaging structure according to claim 1, wherein: A plurality of blind holes are provided on the lower surface of the carrier plate.

3. The packaging structure according to claim 2, wherein: A plurality of the blind holes are evenly distributed on the lower surface of the carrier board.

4. The packaging structure according to claim 2, wherein: The plurality of blind holes are evenly distributed on the edge area of ​​the lower surface of the carrier board and are located inside the through holes.

5. The packaging structure according to claim 2, wherein: The blind hole is a circular arc blind hole.

6. The packaging structure according to any one of claims 1 to 5, characterized in that: A plurality of through holes are evenly spaced and arranged at the edge area of ​​the carrier board.

7. The packaging structure according to any one of claims 1 to 5, characterized in that: The packaging structure further includes a temporary bonding adhesive layer; The temporary bonding adhesive layer is arranged between the carrier board and the plurality of metal base plates.

8. The packaging structure according to any one of claims 1 to 5, characterized in that: The packaging structure further includes bonding wires; The bonding wires are respectively electrically connected between the chip and the corresponding substrate, and between two adjacent chips.

9. The packaging structure according to any one of claims 1 to 5, characterized in that: The carrier plate is made of a material that matches the CTE of the metal base plate.

10. A power module, characterized in that: The power module packaging structure according to any one of claims 1 to 9 is obtained by removing the carrier board and cutting, and the power module comprises: at least one metal base plate; At least one substrate, the substrate being disposed on the corresponding metal base plate; at least one chip, wherein the chip is disposed on the corresponding substrate; at least one external terminal, a first end of the external terminal being fixed to the substrate and electrically connected to the chip; A plastic package body encapsulates the metal bottom plate, the substrate, the chip and part of the external terminals, wherein the second ends of the external terminals pass through the plastic package body.

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