power module

Abstract

The utility model provides a kind of in power module, since the top surface of the first upper metal layer embedded in the first recess is not covered by encapsulation material, and the encapsulation is only connected laterally with the first upper metal layer embedded in the first recess, thus, on the one hand, the top surface of the first upper metal layer with a larger area is exposed, providing a larger area for welding, so that most of the thermal stress is released from the top surface of the first upper metal layer during welding, thereby reducing the thermal stress at the lateral connection, on the other hand, the lateral connection mode takes advantage of the characteristics that the tensile strength and extrusion resistance of thermosetting resin system materials are superior to shear strength, thereby, through the above two aspects, the lateral connection of the encapsulation and the first upper metal layer is not prone to cracking or delamination due to thermal stress, improving the bonding force of the encapsulation and the first substrate and the reliability of the power module.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuits, and in particular to a power module. Background Technology

[0002] A power module is a modular component that integrates multiple power semiconductor devices (such as IGBTs, MOSFETs, diodes, etc.) with drive circuits, protection circuits, thermal management structures, etc., into a single package. Through optimized layout and interconnection technology, it achieves efficient conversion and control of electrical energy.

[0003] The coefficient of thermal expansion of the metal layer is much greater than that of the package material. Therefore, when soldering connection structures for external circuitry onto the upper metal layer of the substrate, the expansion and deformation of the upper metal layer is more severe than that of the package itself. In existing technologies, such as... Figure 1 As shown, since the package 20 includes a thin packaging layer 21 located on part of the upper surface of the upper metal layer 10, and the shear strength of this thin packaging layer 21 is insufficient to resist the thermal stress between the upper metal layer 10 and the package 21 caused by soldering, this location is prone to delamination or cracking. Utility Model Content

[0004] This invention provides a power module to solve the problem that power modules are prone to dents due to the heat generated during soldering.

[0005] The technical solution of this utility model provides a power module, including: The first substrate includes at least a first insulating substrate and a first upper metal layer located on one side surface of the first insulating substrate, the first upper metal layer being used for connection with an external circuit. An encapsulation body for encapsulating the first substrate, wherein the encapsulation body is made of a thermosetting resin system material, wherein at least one first groove is provided in the encapsulation body, wherein the first upper metal layer does not overlap with the bottom wall of the first groove, and a portion of the first upper metal layer is embedded in the bottom wall of the first groove to be exposed, wherein the side surface of the first upper metal layer is laterally connected to the edge of the bottom wall of the first groove, and the connection between the side wall surface of the first groove and the bottom wall surface of the first groove is located outside the first upper metal layer.

[0006] Optionally, the angle between the sidewall of the first groove and the bottom wall of the first groove is in the range of 95° to 115°.

[0007] Optionally, the top surface of the first upper metal layer is recessed relative to the bottom wall surface of the first groove, and the angle between the exposed bottom wall surface of the first groove and the side surface of the bottom wall of the first groove is 90°, or an R-shaped chamfer or a C-shaped chamfer is formed between the exposed top surface of the first groove and the side surface of the bottom wall of the first groove.

[0008] Optionally, the top surface of the first upper metal layer protrudes relative to the bottom wall of the first groove, and the angle between the top surface of the first upper metal layer and the side wall of the first upper metal layer is 90°, or a C-shaped chamfer or an R-shaped chamfer is formed between the top surface of the first upper metal layer and the side wall of the first upper metal layer.

[0009] Optionally, the top surface of the first upper metal layer is flush with the bottom wall surface of the first groove.

[0010] Optionally, the sidewall of the first groove is composed of a stepped structure and a connecting surface. The stepped structure consists of several steps, each step including a tread and a kick surface. The plane where the tread is located is parallel to the surface of the substrate, and the plane where the kick surface is located intersects the surface of the substrate. A C-shaped chamfer or an R-shaped chamfer is formed between the tread and the kick surface. The tread is located above the kick surface. The connecting surface is used to connect the tread farthest from the substrate to the top surface of the package.

[0011] Optionally, the height of the kick surface is greater than or equal to 0.8 mm, and the width of the tread surface is 0.5 mm to 2 mm.

[0012] Optionally, the minimum distance between the connection between the side wall of the first groove and the bottom wall of the first groove and the lateral connection is greater than or equal to 0.25 mm.

[0013] Optional, also includes: A plurality of connection structures are provided, wherein a portion of the connection structure is located within the first groove, and one end of the connection structure is connected to the exposed top surface of the upper metal layer, the remaining portion of the connection structure is located outside the first groove, and the other end of the connection structure is used to connect to the external circuit. An insulating layer is filled within the first groove to cover a portion of the connection structure located within the first groove and the exposed upper surface of the first upper metal layer.

[0014] Optionally, the material of the encapsulation body is further selected from one of multifunctional epoxy resin, bisphenol F type epoxy resin, and biphenyl type epoxy resin.

[0015] Optionally, the first substrate further includes: a first lower metal layer located on the other side surface of the first insulating substrate, the other side surface of the first insulating substrate facing away from the surface of the first insulating substrate on the side where the first upper metal layer is located, and the package exposes at least a portion of the surface of the first lower metal layer facing away from the first insulating substrate.

[0016] Optional, also includes: The second substrate is located on the first upper metal layer and is encapsulated by the package. The area of ​​the second substrate is smaller than that of the first substrate. The second substrate includes a second lower metal layer, a second insulating substrate, and a second upper metal layer stacked sequentially from bottom to top. The second lower metal layer faces the first substrate. The package also has a second groove. The second upper metal layer does not overlap with the bottom wall of the second groove. Part of the second upper metal layer is embedded in the bottom wall of the second groove to be exposed. Furthermore, the side of the second upper metal layer is laterally connected to the edge of the bottom wall of the second groove. The connection between the side wall of the second groove and the bottom wall of the second groove is located outside the second upper metal layer. And / or, a chip located on the first upper metal layer and fully encapsulated by the package.

[0017] Optionally, the connection between at least a portion of the sidewall of the first groove and the corresponding portion of the bottom wall is located outside the first upper metal layer.

[0018] Compared with the prior art, the technical solution of this utility model has the following beneficial effects: In a power module provided by the technical solution of the present invention, since at least one first groove is provided in the package and a portion of the first upper metal layer is embedded in the bottom wall of the first groove to be exposed, the connection between the first upper metal layer and the external circuit can be realized through the exposed first upper metal layer.

[0019] Furthermore, since the first upper metal layer does not overlap with the bottom wall of the first groove, the side of the first upper metal layer is laterally connected to the edge of the bottom wall of the first groove, and the connection between the side wall of the first groove and the bottom wall of the first groove is located outside the first upper metal layer, the first upper metal layer that is not embedded in the bottom wall of the first groove is encapsulated by the encapsulation body and located outside the first groove. At the same time, the side of the first upper metal layer that is embedded in the bottom wall of the first groove is laterally connected to the bottom wall of the first groove, and its top surface is completely exposed (not covered or blocked by the encapsulation body).

[0020] On the one hand, since the connection between the sidewall and bottomwall of the first groove is located outside the first upper metal layer, the encapsulation layer on the top surface of the first upper metal layer, which is not embedded in the bottom wall of the first groove, is relatively thick. On the other hand, since the first upper metal layer is laterally connected to the bottom wall of the first groove and its top surface is completely exposed (not covered or blocked by the package), the exposed area of ​​the first upper metal layer is large, providing a large soldering area when forming a connection with the external circuit. This not only allows most of the thermal stress to be released from the top surface of the first upper metal layer during soldering, reducing thermal stress at the lateral connection, but also leverages the superior tensile and compressive strength of thermosetting resin materials compared to their shear strength through the lateral connection method. Therefore, the connection at the lateral connection between the package and the first upper metal layer is reliable, and a thinner encapsulation layer is avoided on the top surface outside the lateral connection. Consequently, the package and the first upper metal layer are less prone to cracking or delamination due to thermal stress, improving the bonding strength between the package and the substrate and the reliability of the power module.

[0021] Furthermore, since the top surface of the first upper metal layer is recessed relative to the bottom wall of the first groove, the chamfer between the exposed bottom wall of the first groove and the side wall of the first groove is an R-shaped chamfer or a C-shaped chamfer. This creates a transition area between the top surface of the first upper metal layer and the bottom wall of the first groove, making it less prone to overflow after injection molding. This reduces the need for overflow handling and simplifies the process. In addition, this transition area can also alleviate stress during injection molding, thereby improving the reliability of the power module.

[0022] Furthermore, since the top surface of the first upper metal layer protrudes relative to the bottom wall of the first groove, the chamfer between the top surface and the side wall of the first upper metal layer is a C-shaped chamfer or a R-shaped chamfer, creating a transition area between the top surface of the first upper metal layer and the bottom wall of the first groove. This makes it less likely for the package to overflow after injection molding, thereby reducing the need for overflow handling and simplifying the process. In addition, this transition area can also alleviate stress during injection molding, improving the reliability of the power module. Attached Figure Description

[0023] Figure 1 This is a cross-sectional structural diagram of a power module; Figure 2 This is a cross-sectional structural diagram of the power module provided in the first embodiment of this utility model; Figure 3 This is a cross-sectional structural diagram of the power module provided in the second embodiment of the present invention; Figure 4 This is a cross-sectional structural diagram of the power module provided in the third embodiment of this utility model; Figure 5 This is a cross-sectional structural diagram of the power module provided in the fourth embodiment of this utility model; Figure 6 This is a cross-sectional structural diagram of the power module provided in the fifth embodiment of this utility model; Figure 7 This is a cross-sectional structural diagram of the power module provided in the sixth embodiment of this utility model; Figure 8 This is a cross-sectional structural schematic diagram of the power module provided in the seventh embodiment of this utility model; Figure 9 This is a cross-sectional structural diagram of the power module provided in the eighth embodiment of this utility model; Figure 10 This is a cross-sectional structural diagram of the power module provided in the ninth embodiment of this utility model.

[0024] Figure label: 1-First upper metal layer; 2-First insulating substrate; 3-First groove; 4-Package; 5- Lower metal layer; 6-Second upper metal layer; 7-Second insulating substrate; 8-Second lower metal layer; 9-Second groove. Detailed Implementation

[0025] As in the background art, because the shear strength of a thinner encapsulation layer is insufficient to resist the thermal stress between the metal layer and the encapsulation layer caused by welding, a thinner encapsulation material layer on part of the upper surface of the first upper metal layer is prone to delamination or cracking, thereby reducing the bonding force between the encapsulation material layer and the first upper metal layer, and thus reducing the reliability of the power module.

[0026] In view of this, the present invention creatively proposes a power module, comprising: The first substrate includes at least a first insulating substrate and a first upper metal layer located on one side surface of the first insulating substrate, the first upper metal layer being used for connection with an external circuit. An encapsulation body for encapsulating the first substrate, wherein the encapsulation body is made of a thermosetting resin system material, wherein at least one first groove is provided in the encapsulation body, wherein the first upper metal layer does not overlap with the bottom wall of the first groove, and a portion of the first upper metal layer is embedded in the bottom wall of the first groove to be exposed, wherein the side surface of the first upper metal layer is laterally connected to the edge of the bottom wall of the first groove, and the connection between the side wall surface of the first groove and the bottom wall surface of the first groove is located outside the first upper metal layer.

[0027] The connection between the package and the first upper metal layer at the lateral connection is reliable, and a thin package layer is avoided on the top surface other than the lateral connection. As a result, the package and the first upper metal layer are less likely to crack or delaminate due to thermal stress, which improves the bonding force between the package and the substrate and the reliability of the power module.

[0028] The embodiments of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0029] Figure 2 This is a cross-sectional structural diagram of the power module provided in the first embodiment of this utility model.

[0030] Please refer to Figure 2 The power module includes a first substrate and a package 4.

[0031] In the first embodiment, the first substrate includes a first insulating substrate 2, a first upper metal layer 1 and a first lower metal layer 5 located on one side of the first insulating substrate 2. The first upper metal layer 1 is used to connect with an external circuit, and the first lower metal layer 5 is located on the other side of the first insulating substrate 2, with the other side of the first insulating substrate 2 facing away from the surface of the first insulating substrate 2 where the first upper metal layer 1 is located.

[0032] The material of the first insulating substrate 2 may be, for example, ceramic.

[0033] In the first embodiment, the first substrate is encapsulated by a package 4, and at least one first groove 3 is provided in the package 4. The first upper metal layer 1 does not overlap with the bottom wall of the first groove 3, and a portion of the first upper metal layer 1 is embedded in the bottom wall of the first groove 3 to be exposed. The side surface of the first upper metal layer 1 is laterally connected to the edge of the bottom wall of the first groove 3. The connection between the side wall surface of the first groove 3 and the bottom wall surface of the first groove 3 is located outside the first upper metal layer 1. The side surface of the lower metal layer 5 facing away from the first insulating substrate 2 is exposed relative to the package 4 for heat dissipation. Specifically, the bottom wall of the first groove 3 is used to characterize the package 4 between the bottom surface of the first groove 3 and the top surface of the first insulating substrate 2. The top surface of the package 4 is the bottom wall surface, and the connection between a portion of the side wall surface of the first groove 3 and the corresponding portion of the bottom wall surface is located outside the first upper metal layer 1.

[0034] In addition, package 4 is also used to package power semiconductors and other power module components.

[0035] In the first embodiment, the material of the encapsulation body 4 is a thermosetting resin system material, including multifunctional epoxy resin, bisphenol F type epoxy resin or biphenyl type epoxy resin, etc.

[0036] In the first embodiment, the minimum distance d between the connection between the side wall surface of the first groove 3 and the bottom wall surface of the first groove 3 and the lateral connection is greater than or equal to 0.25 mm.

[0037] In the first embodiment, the shape of the projection of the first groove 3 onto the plane where the first insulating substrate 2 is located can be, for example, square, polygonal, circular, or elliptical. When the shape of the projection of the first groove 3 onto the plane where the first insulating substrate 2 is located is square, the connection between one / two / three / four sidewalls of the first groove 3 and the corresponding bottom wall is located outside the first upper metal layer 1.

[0038] In the first embodiment, the angle α between the side wall of the first groove 3 and the bottom wall of the first groove 3 is in the range of 95°~115°, which makes the draft angle larger when forming the package 4, thereby making the draft of the package 4 simpler.

[0039] In the first embodiment, the top surface of the first upper metal layer 1 is flush with the bottom wall surface of the first groove 3.

[0040] In the first embodiment, since the thickness of the package 4 on the top surface of the first upper metal layer 1 located inside the package 4 is relatively large, the package 4 on the top surface of the first upper metal layer 1 can resist the thermal stress between the first upper metal layer 1 and the package 4 caused by welding, thereby avoiding delamination or cracking at the contact position between the first upper metal layer 1 and the package 4, thereby improving the bonding force between the package 4 and the first substrate 1 and the reliability of the power module.

[0041] In the first embodiment, the power module further includes several connection structures and an insulating layer.

[0042] The connecting structure is located within the first groove 3, with one end connected to the exposed top surface of the first upper metal layer 1. The remaining portion of the connecting structure is located outside the first groove 3, and the other end of the connecting structure is used for connection to an external circuit. An insulating layer fills the first groove 3 to cover the portion of the connecting structure located within the first groove 3 and the exposed upper surface of the first upper metal layer 1.

[0043] The insulating layer can be, for example, an insulating adhesive.

[0044] Figure 3 This is a cross-sectional structural diagram of the power module provided in the second embodiment of this utility model.

[0045] In the second embodiment, please refer to Figure 3 The difference between this embodiment and the first embodiment is that the relative height between the top surface of the first upper metal layer 1 and the bottom wall surface of the first groove 3 is such that the top surface of the first upper metal layer 1 is recessed relative to the bottom wall surface of the first groove 3. Furthermore, the angle between the exposed bottom wall surface of the first groove 3 and the side surface of the bottom wall of the first groove 3 is 90°.

[0046] Figure 4 This is a cross-sectional structural diagram of the power module provided in the third embodiment of this utility model.

[0047] In the third embodiment, please refer to Figure 4 The difference between this embodiment and the second embodiment is that an R-shaped chamfer is formed between the bottom wall surface of the exposed first groove 3 and the side surface of the bottom wall of the first groove 3.

[0048] In this design, because the top surface of the first upper metal layer 1 is recessed relative to the bottom wall surface of the first groove 3, a portion of the bottom wall's side surface is exposed. Furthermore, an R-shaped chamfer (either an R-shaped or C-shaped chamfer) is formed between the exposed bottom wall surface of the first groove 3 and its side surface, creating a transition area between the top surface of the first upper metal layer 1 and the bottom wall surface of the first groove 3. This prevents overflow in the package 4 after injection molding, reducing the need for overflow handling and simplifying the process. Additionally, this transition area can alleviate stress during injection molding, improving the reliability of the power module.

[0049] Figure 5 This is a cross-sectional structural diagram of the power module provided in the fourth embodiment of this utility model.

[0050] In the fourth embodiment, please refer to Figure 5The difference between this embodiment and the third embodiment is that a C-shaped chamfer is formed between the bottom wall surface of the exposed first groove 3 and the side surface of the bottom wall of the first groove 3, that is, a C-shaped chamfer is formed between the bottom wall surface of the exposed first groove 3 and the side surface of the bottom wall to replace the R-shaped chamfer. Similar to the R-shaped chamfer, the C-shaped chamfer can also reduce the process of handling overflow and is used to relieve stress during injection molding to improve the reliability of the power module.

[0051] It needs to be understood that, although in Figure 5 The first upper metal layer 1 at the cross-section shown is fully exposed by the first groove 3, but at least a portion of the first upper metal layer 1 at other locations on the first substrate is encapsulated and covered by the package 4.

[0052] Figure 6 This is a cross-sectional structural diagram of the power module provided in the fifth embodiment of this utility model.

[0053] In the fifth embodiment, please refer to Figure 6 The difference between this embodiment and the first embodiment is that the relative height between the top surface of the first upper metal layer 1 and the bottom wall surface of the first groove 3 is such that the top surface of the first upper metal layer 1 protrudes relative to the bottom wall surface of the first groove 3. Furthermore, the angle between the top surface of the first upper metal layer 1 and the side wall surface of the first upper metal layer 1 is 90°.

[0054] Figure 7 This is a cross-sectional structural diagram of the power module provided in the sixth embodiment of this utility model.

[0055] In the sixth embodiment, please refer to Figure 7 The difference between this embodiment and the fifth embodiment is that an R-shaped chamfer is formed between the top surface of the first upper metal layer 1 and the side wall surface of the first upper metal layer 1.

[0056] Because the top surface of the first upper metal layer 1 protrudes relative to the bottom wall of the first groove 3, part of the side surface of the first upper metal layer 1 is exposed. Furthermore, because a chamfer (R-angle) is formed between the top surface of the first upper metal layer 1 and the side wall of the first upper metal layer 1, a transition area exists between the top surface of the first upper metal layer 1 and the bottom wall of the first groove 3. This makes it less likely for the package 4 to overflow after injection molding, thereby reducing the need for overflow handling and simplifying the process. In addition, this transition area can also alleviate stress during injection molding, thus improving the reliability of the power module.

[0057] Figure 8 This is a cross-sectional structural diagram of the power module provided in the seventh embodiment of this utility model.

[0058] In the seventh embodiment, please refer to Figure 8The difference between this embodiment and the sixth embodiment is that a C-shaped chamfer is formed between the top surface of the first upper metal layer 1 and the sidewall surface of the first upper metal layer 1 instead of an R-shaped chamfer. Similar to the R-shaped chamfer, the C-shaped chamfer can also reduce the process of handling overflow and is used to relieve stress during injection molding to improve the reliability of the power module.

[0059] Figure 9 This is a cross-sectional structural diagram of the power module provided in the eighth embodiment of this utility model.

[0060] In the eighth embodiment, please refer to Figure 9 The difference between this embodiment and the first embodiment is that the shape of the side wall of the first groove 3 is different. That is, the side wall of the first groove 3 is composed of a stepped structure and a connecting surface. The stepped structure is composed of several steps. Each step includes a tread surface and a kick surface. The plane where the tread surface is located is parallel to the surface of the first insulating substrate 2. The plane where the kick surface is located intersects with the surface of the first insulating substrate 2. A C-shaped chamfer or an R-shaped chamfer is formed between the tread surface and the kick surface. The tread surface is located above the kick surface. The connecting surface is used to connect the tread surface farthest from the first insulating substrate 2 to the top surface of the package 4. A C-shaped chamfer or an R-shaped chamfer is formed between the connecting surface and the tread surface connected to it.

[0061] In the eighth embodiment, the height h of the kick surface is greater than or equal to 0.8 mm, and the width k of the tread surface is 0.5 mm to 2 mm.

[0062] Figure 10 This is a cross-sectional structural diagram of the power module provided in the ninth embodiment of this utility model.

[0063] In the ninth embodiment, the power module further includes: a second substrate and / or a chip.

[0064] In the ninth embodiment, please refer to Figure 10 The second substrate is located on the first upper metal layer 1 and encapsulated by the package 4. The area of ​​the second substrate is smaller than that of the first substrate. The second substrate includes a second lower metal layer 8, a second insulating substrate 7, and a second upper metal layer 6 stacked sequentially from bottom to top. The package 4 also has a second groove 9. The second upper metal layer 6 does not overlap with the bottom wall of the second groove 9. Part of the second upper metal layer 6 is embedded in the bottom wall of the second groove 9 and exposed. Furthermore, the side surface of the second upper metal layer 6 is laterally connected to the edge of the bottom wall of the second groove 9. The connection between the side wall surface and the bottom wall surface of the second groove 9 is located outside the second upper metal layer 6. The lower metal layer 5 is in contact with the second upper metal layer 6, and the side surface of the second lower metal layer 8 facing away from the second substrate is exposed relative to the package 4 for heat dissipation.

[0065] The reliable connection at the lateral connection between the package 4 and the second upper metal layer 6 makes the connection between the package 4 and the second upper metal layer 6 less prone to cracking or delamination due to thermal stress, thus improving the bonding strength between the package 4 and the substrate and the reliability of the power module. The specific reason is similar to the lateral connection between the package 4 and the first upper metal layer 1 in the above embodiments; please refer to the relevant descriptions, which will not be repeated here.

[0066] In the ninth embodiment, the chip is located on the first upper metal layer 1, and the chip is completely encapsulated by the package 4, that is, the chip is not exposed outside the package 4.

[0067] In summary, in the power module provided by the technical solution of the present invention, since at least one first groove 3 is provided in the package 4 and a portion of the first upper metal layer is embedded in the bottom wall of the first groove to be exposed, the first upper metal layer 1 can be connected to the external circuit through the exposed first upper metal layer 1.

[0068] Furthermore, since the first upper metal layer 1 does not overlap with the bottom wall of the first groove 3, the side of the first upper metal layer is laterally connected to the edge of the bottom wall of the first groove, and the connection between the side wall of the first groove and the bottom wall of the first groove is located outside the first upper metal layer, the first upper metal layer that is not embedded in the bottom wall of the first groove is encapsulated by the encapsulation body and located outside the first groove. At the same time, the side of the first upper metal layer that is embedded in the bottom wall of the first groove is laterally connected to the bottom wall of the first groove, and its top surface is completely exposed (not covered or blocked by the encapsulation body).

[0069] On the one hand, since the connection between the side wall and the bottom wall of the first groove is located outside the first upper metal layer, the encapsulation layer on the top surface of the first upper metal layer 1, which is not embedded in the bottom wall of the first groove, is thicker. On the other hand, since the first upper metal layer 1 is laterally connected to the bottom wall of the first groove 3 and its top surface is completely exposed (not covered or blocked by the encapsulation body 4), the exposed area of ​​the first upper metal layer 1 is large, and it provides a large welding area when forming a connection with the external circuit. Thus, not only can most of the thermal stress be released from the top surface of the first upper metal layer 1 during welding, reducing the thermal stress at the lateral connection, but the lateral connection method also takes advantage of the characteristics of thermosetting materials that have better tensile and compressive strength than shear strength. Therefore, the connection between the package 4 and the first upper metal layer 1 at the lateral connection is reliable, and a thinner package layer is avoided on the top surface other than the lateral connection. As a result, the package 4 and the first upper metal layer 1 are not easily cracked or delaminated due to thermal stress, which improves the bonding force between the package 4 and the substrate and the reliability of the power module.

[0070] Furthermore, since the top surface of the first upper metal layer 1 is recessed relative to the bottom wall surface of the first groove 3, the chamfer between the exposed bottom wall surface of the first groove 3 and the side surface of the bottom wall of the first groove is an R-shaped chamfer or a C-shaped chamfer. This creates a transition area between the top surface of the first upper metal layer 1 and the bottom wall surface of the first groove 3, making it less likely for the package 4 to overflow after injection molding. This reduces the need for overflow handling and simplifies the process. In addition, this transition area can also be used to alleviate stress during injection molding, thereby improving the reliability of the power module.

[0071] Furthermore, since the top surface of the first upper metal layer 1 protrudes relative to the bottom wall surface of the first groove 3, the chamfer between the top surface of the first upper metal layer 1 and the side wall surface of the first upper metal layer 1 is a C-shaped chamfer or an R-shaped chamfer. This creates a transition area between the top surface of the first upper metal layer 1 and the bottom wall surface of the first groove 3, making it less likely for the package 4 to overflow after injection molding. This reduces the need for overflow handling and simplifies the process. In addition, this transition area can also be used to alleviate stress during injection molding, thereby improving the reliability of the power module.

[0072] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A power module, characterized in that, include: The first substrate includes at least a first insulating substrate and a first upper metal layer located on one side surface of the first insulating substrate, the first upper metal layer being used for connection with an external circuit. An encapsulation body for encapsulating the first substrate, wherein the encapsulation body is made of a thermosetting resin system material, wherein at least one first groove is provided in the encapsulation body, wherein the first upper metal layer does not overlap with the bottom wall of the first groove, and a portion of the first upper metal layer is embedded in the bottom wall of the first groove to be exposed, wherein the side surface of the first upper metal layer is laterally connected to the edge of the bottom wall of the first groove, and the connection between the side wall surface of the first groove and the bottom wall surface of the first groove is located outside the first upper metal layer.

2. The power module according to claim 1, characterized in that, The angle between the sidewall of the first groove and the bottom wall of the first groove is in the range of 95° to 115°.

3. The power module according to claim 2, characterized in that, The top surface of the first upper metal layer is recessed relative to the bottom wall surface of the first groove, and the angle between the exposed bottom wall surface of the first groove and the side surface of the bottom wall of the first groove is 90°, or an R chamfer or C chamfer is formed between the exposed bottom wall surface of the first groove and the side surface of the bottom wall of the first groove.

4. The power module according to claim 2, characterized in that, The top surface of the first upper metal layer protrudes from the bottom wall of the first groove, and the angle between the top surface of the first upper metal layer and the side wall of the first upper metal layer is 90°. Alternatively, a C-shaped chamfer or an R-shaped chamfer is formed between the top surface of the first upper metal layer and the side wall of the first upper metal layer.

5. The power module according to claim 2, characterized in that, The top surface of the first upper metal layer is flush with the bottom wall surface of the first groove.

6. The power module according to claim 2, characterized in that, The sidewall of the first groove is composed of a stepped structure and a connecting surface. The stepped structure consists of several steps, each step including a tread and a kick surface. The plane where the tread is located is parallel to the surface of the substrate, and the plane where the kick surface is located intersects the surface of the substrate. A C-shaped chamfer or an R-shaped chamfer is formed between the tread and the kick surface. The tread is located above the kick surface. The connecting surface is used to connect the tread farthest from the substrate to the top surface of the package.

7. The power module according to claim 6, characterized in that, The height of the kick surface is greater than or equal to 0.8 mm, and the width of the tread surface is 0.5 mm to 2 mm.

8. The power module according to claim 1, characterized in that, The minimum distance between the connection between the side wall of the first groove and the bottom wall of the first groove and the lateral connection is greater than or equal to 0.25 mm.

9. The power module according to claim 1, characterized in that, Also includes: A plurality of connection structures are provided, wherein a portion of the connection structure is located within the first groove, and one end of the connection structure is connected to the exposed top surface of the upper metal layer, the remaining portion of the connection structure is located outside the first groove, and the other end of the connection structure is used to connect to the external circuit. An insulating layer is filled within the first groove to cover a portion of the connection structure located within the first groove and the exposed upper surface of the first upper metal layer.

10. The power module according to claim 1, characterized in that, The material of the encapsulation body is further selected from one of multifunctional epoxy resin, bisphenol F type epoxy resin, and biphenyl type epoxy resin.

11. The power module according to claim 1, characterized in that, The first substrate further includes: a first lower metal layer located on the other side surface of the first insulating substrate, the other side surface of the first insulating substrate facing away from the surface of the first insulating substrate on the side where the first upper metal layer is located, and the package exposes at least a portion of the surface of the first lower metal layer facing away from the first insulating substrate.

12. The power module according to claim 1, characterized in that, Also includes: The second substrate is located on the first upper metal layer and is encapsulated by the package. The area of ​​the second substrate is smaller than that of the first substrate. The second substrate includes a second lower metal layer, a second insulating substrate, and a second upper metal layer stacked sequentially from bottom to top. The second lower metal layer faces the first substrate. The package also has a second groove. The second upper metal layer does not overlap with the bottom wall of the second groove. Part of the second upper metal layer is embedded in the bottom wall of the second groove to be exposed. Furthermore, the side of the second upper metal layer is laterally connected to the edge of the bottom wall of the second groove. The connection between the side wall of the second groove and the bottom wall of the second groove is located outside the second upper metal layer. And / or, a chip located on the first upper metal layer and fully encapsulated by the package.

13. The power module according to claim 1, characterized in that, The connection between at least a portion of the sidewall of the first groove and the corresponding portion of the bottom wall is located outside the first upper metal layer.

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