A plastic-encapsulated power module structure

Abstract

This invention provides a molded power module structure, comprising: a substrate, wherein the first layer of the substrate is a wiring layer, the second layer is an insulating layer, and at least one molding compound covers the upper surface of the wiring layer; a power chip disposed on the substrate; and a power terminal, wherein the power terminal is an integrally molded structure, divided into a first metal segment and a second metal segment, and the thickness of the first metal segment is greater than the thickness of the second metal segment; the power terminal is electrically connected to the power chip through its second metal segment; the second metal segment and part of the first metal segment of the power terminal are covered by the molding compound, and the remaining first metal segment is exposed outside the molding compound. This invention can improve the vibration resistance of the terminals of the molded power module.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor technology, specifically to a plastic-encapsulated power module structure. Background Technology

[0002] Power modules are widely used in new energy vehicles, new energy power generation, smart grids, and transportation electrification. In some areas, such as new energy vehicle controllers, especially hybrid electric vehicle controllers, there are higher requirements for the vibration resistance of power modules. The structural design of traditional power modules does not take into account the high vibration operating conditions of hybrid electric vehicles. Under high vibration conditions, fatigue fracture of module terminals may occur, leading to module failure and safety hazards.

[0003] Tesla's T-PAK module is a plastic-encapsulated module containing two parallel chips forming a single transistor. The module terminals connect to electrodes on the chip surface and extend beyond the module's exterior. The terminals have a uniform thickness. However, due to their relatively low strength, these terminals are prone to fatigue fracture under high-vibration conditions, leading to module failure and potential safety hazards.

[0004] Therefore, how to improve the vibration resistance of power modules is a focus of attention for those skilled in the art. Utility Model Content

[0005] The purpose of this invention is to propose a plastic-encapsulated power module structure that can improve the vibration resistance of the power module terminals.

[0006] To achieve the above objectives, this utility model provides a plastic-encapsulated power module structure, comprising: A substrate, wherein the first layer of the substrate is a wiring layer, the second layer is an insulating layer, and at least one molding compound covers the upper surface of the wiring layer; A power chip is disposed on the substrate; The power terminal is an integrally formed structure, divided into a first metal segment and a second metal segment, wherein the thickness of the first metal segment is greater than the thickness of the second metal segment; the power terminal is electrically connected to the power chip through its second metal segment. The second metal segment and part of the first metal segment of the power terminal are covered by the encapsulation, while the remaining first metal segment is exposed outside the encapsulation.

[0007] In an alternative embodiment, the thickness gradually transitions at the junction of the first metal segment and the second metal segment; or... The thicknesses of the first metal segment and the second metal segment transition directly.

[0008] In an optional embodiment, the molded power module structure further includes a first signal terminal and a second signal terminal, both of which are electrically connected to the power chip.

[0009] In an optional embodiment, the first signal terminal is a metal sheet of uniform thickness, electrically connected to the power chip via a connecting wire, wherein the thickness of the metal sheet is the same as the thickness of the first metal segment of the power terminal; and / or, The second signal terminal is a metal sheet of equal thickness, which is electrically connected to the power chip via a connecting wire. The thickness of the metal sheet is the same as the thickness of the first metal segment of the power terminal.

[0010] In an optional embodiment, the first signal terminal is a one-piece molded structure, divided into a first metal segment and a second metal segment, wherein the thickness of the first metal segment of the first signal terminal is greater than the thickness of the second metal segment, and the first signal terminal is electrically connected to the power chip through its second metal segment; the second metal segment and part of the first metal segment of the first signal terminal are covered by the molding compound, and the remaining first metal segment is exposed outside the molding compound; and / or, The second signal terminal is an integrally molded structure, divided into a first metal segment and a second metal segment. The thickness of the first metal segment of the second signal terminal is greater than the thickness of the second metal segment. The second signal terminal is electrically connected to the power chip through its second metal segment. The second metal segment and part of the first metal segment of the second signal terminal are covered by the molding compound, while the remaining first metal segment is exposed outside the molding compound.

[0011] In the alternative embodiment, the first signal terminal, the second signal terminal, and the power terminal are all separate entities; or, the first signal terminal is a separate entity, while the second signal terminal and the power terminal are a single unit.

[0012] In an optional embodiment, the power chip includes a first electrode, a second electrode, and a third electrode; The second metal segment of the power terminal is connected to the second electrode of the power chip, the first signal terminal is connected to the third electrode of the power chip, and the second signal terminal is connected to the second electrode of the power chip. The first electrode of the power chip is connected to the wiring layer through a first solder layer.

[0013] In an optional configuration, the first signal terminal and the second signal terminal are soldered terminals or crimped terminals.

[0014] In an optional configuration, the thickness of the second metal segment of the power terminal is less than 0.5 mm, and the thickness of the first metal segment is greater than 0.7 mm.

[0015] In the optional solution, the first solder layer is sintered silver, solder, or conductive silver paste.

[0016] The beneficial effects of this utility model are as follows: The power terminals of this invention adopt an integral structure with varying thicknesses. The connection between the power terminals and the chip surface is thinner, which avoids the reliability risks caused by connecting thick terminals to the chip surface. At the same time, the external terminals are thicker, which improves the vibration resistance of the power module terminals. Attached Figure Description

[0017] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which the same reference numerals generally represent the same components.

[0018] Figure 1 This is a top view of a plastic-encapsulated power module structure according to an embodiment of the present invention.

[0019] Figure 2 This is a side view of a plastic-encapsulated power module structure according to an embodiment of the present invention.

[0020] Figure 3 This is a top view of another plastic-encapsulated power module structure in one embodiment of the present invention.

[0021] Figure 4 This is a side view of another plastic-encapsulated power module structure in one embodiment of the present invention.

[0022] Figure label: 1-Encapsulation; 20-First signal terminal; 21-Power terminal; 22-Second signal terminal; 201-First metal segment; 202-Second metal segment. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and drawings. However, it should be noted that the concept of the present invention can be implemented in many different forms and is not limited to the specific embodiments described herein. The accompanying drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0024] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this utility model, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion.

[0025] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0027] Example Reference Figures 1 to 4 This embodiment provides a molded power module structure, including: A substrate, wherein the first layer of the substrate is a wiring layer, the second layer is an insulating layer, and at least one molding compound 1 covers the upper surface of the wiring layer; A power chip is disposed on the substrate; The power terminal 21 is an integrally formed structure. The power terminal 21 is sheet-shaped and divided into a first metal segment 201 and a second metal segment 202. The thickness of the first metal segment 201 is greater than the thickness of the second metal segment 202. The power terminal 21 is electrically connected to the power chip through its second metal segment 202. The second metal segment 202 and part of the first metal segment 201 of the power terminal 21 are both covered by the encapsulation 1, while the remaining first metal segment 201 is exposed outside the encapsulation 1.

[0028] In this embodiment, the molded power module structure further includes a first signal terminal 20 and a second signal terminal 22, both of which are electrically connected to the power chip. The power terminal 21, the first signal terminal 20, and the second signal terminal 22 all extend from the side of the molded body 1.

[0029] In this embodiment, the first signal terminal 20 is an integrally molded structure, divided into a first metal segment and a second metal segment. The thickness of the first metal segment of the first signal terminal 20 is greater than the thickness of the second metal segment. The first signal terminal 20 is electrically connected to the power chip through its second metal segment. The second metal segment and part of the first metal segment of the first signal terminal 20 are covered by the molding compound 1, and the remaining first metal segment is exposed outside the molding compound 1. The second signal terminal 22 is an integrally molded structure, divided into a first metal segment and a second metal segment. The thickness of the first metal segment of the second signal terminal 22 is greater than the thickness of the second metal segment. The second signal terminal 22 is electrically connected to the power chip through its second metal segment. The second metal segment and part of the first metal segment of the second signal terminal 22 are covered by the molding compound 1, and the remaining first metal segment is exposed outside the molding compound 1.

[0030] In another embodiment, the first signal terminal is a metal sheet of equal thickness, electrically connected to the power chip via a connecting wire, and the thickness of the metal sheet is the same as the thickness of the first metal segment of the power terminal; the second signal terminal is a metal sheet of equal thickness, electrically connected to the power chip via a connecting wire, and the thickness of the metal sheet is the same as the thickness of the first metal segment of the power terminal.

[0031] In this embodiment, the thickness of the front end of the first metal segment of the power terminal 21 / first signal terminal 20 / second signal terminal 22 gradually transitions at the connection point with the second metal segment. In other embodiments, the connection point can also be a direct transition.

[0032] Figure 1 and Figure 2 In this configuration, the first signal terminal 20 is a separate entity, while the second signal terminal 22 and the power terminal 21 are a single unit. Figure 3 and Figure 4 In this configuration, the first signal terminal 20, the second signal terminal 22, and the power terminal 21 are all individual components. The first signal terminal 20 and the second signal terminal 22 can be soldered terminals or crimped terminals.

[0033] The insulating layer material of the substrate can be aluminum oxide, aluminum nitride, zirconium oxide, silicon nitride, epoxy resin, organosilicon, etc.

[0034] Power chips can be diode chips, MOSFET chips, IGBT chips, HEMT chips, JFET chips, BJT chips, or SCR chips.

[0035] When the power chip is a MOSFET chip, the power chip contains a first terminal, a second terminal, and a third terminal; the first terminal is the drain, the second terminal is the source, and the third terminal is the gate. The second metal segment 202 of each power terminal 21 is connected to the second terminal of the power chip, the second metal segment of the first signal terminal 20 is connected to the third terminal of the power chip, the second metal segment of the second signal terminal 22 is connected to the second terminal of the power chip, and the first terminal of the power chip is connected to the wiring layer through a first solder layer. The first solder layer can be a conductive material such as sintered silver, solder, or conductive silver paste.

[0036] In this embodiment, the power terminal is made of copper, the thickness of the second metal segment 202 of the power terminal is less than 0.5 mm, and the thickness of the first metal segment 201 is greater than 0.7 mm. The power terminal 21, the first signal terminal 20, and the second signal terminal 22 are all led out from the side of the encapsulation 1.

[0037] Traditional power module terminal width / thickness designs prioritize electrical performance, making them prone to fracture failure in vibration environments. Existing terminal structures exhibit significant responses in XYZ triaxial frequency sweep and random superimposed vibration tests, leading to fatigue cumulative damage and noticeable stress concentration at the terminal and module package. This embodiment employs a unequal-thickness, integral terminal structure, mitigating the reliability risks associated with thick copper connections on the chip surface and enhancing vibration resistance. For example, increasing the thickness of the first metal segment from 0.4mm to 0.8mm significantly improves vibration resistance under the same vibration conditions (random vibration, 50-2000Hz equivalent 6.8G acceleration load). The number of failure cycles increases from approximately 10^5 in the traditional structure to over 10^6, and the first-order natural frequency also improves by about 20%, enhancing low-frequency resonance.

[0038] In addition, compared to the traditional method of leading the terminal out from the side of the encapsulation, the maximum stress at the root of the terminal is reduced from about 180MPa to about 55MPa, which is lower than the fatigue limit of the material (taking copper as an example, and considering the fatigue limit with 30% of the yield strength).

[0039] The above description is only a description of the preferred embodiment of the present utility model and is not intended to limit the scope of the present utility model in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A plastic-encapsulated power module structure, characterized in that, include: A substrate, wherein the first layer of the substrate is a wiring layer, the second layer is an insulating layer, and at least one molding compound covers the upper surface of the wiring layer; The insulating layer is made of aluminum oxide, aluminum nitride, zirconium oxide, or silicon nitride. A power chip is disposed on the substrate; The power terminal is an integrally formed structure, and the power terminal is in the form of a sheet; it is divided into a first metal segment and a second metal segment, and the thickness of the first metal segment is greater than the thickness of the second metal segment; the power terminal is electrically connected to the power chip through its second metal segment; The second metal segment and part of the first metal segment of the power terminal are covered by the encapsulation, while the remaining first metal segment is exposed outside the encapsulation.

2. The encapsulated power module structure as described in claim 1, characterized in that, At the junction of the first metal segment and the second metal segment, the thickness gradually transitions; or, The thicknesses of the first metal segment and the second metal segment transition directly.

3. The encapsulated power module structure as described in claim 1, characterized in that, The encapsulated power module structure also includes a first signal terminal and a second signal terminal, both of which are electrically connected to the power chip.

4. The plastic-encapsulated power module structure as described in claim 3, characterized in that, The first signal terminal is a metal sheet of uniform thickness, electrically connected to the power chip via a connecting wire. The thickness of the metal sheet is the same as the thickness of the first metal segment of the power terminal; and / or, The second signal terminal is a metal sheet of equal thickness, which is electrically connected to the power chip via a connecting wire. The thickness of the metal sheet is the same as the thickness of the first metal segment of the power terminal.

5. The plastic-encapsulated power module structure as described in claim 3, characterized in that, The first signal terminal is an integrally molded structure, divided into a first metal segment and a second metal segment. The thickness of the first metal segment of the first signal terminal is greater than the thickness of the second metal segment. The first signal terminal is electrically connected to the power chip through its second metal segment. The second metal segment and part of the first metal segment of the first signal terminal are covered by the molding compound, while the remaining first metal segment is exposed outside the molding compound. And / or, The second signal terminal is an integrally molded structure, divided into a first metal segment and a second metal segment. The thickness of the first metal segment of the second signal terminal is greater than the thickness of the second metal segment. The second signal terminal is electrically connected to the power chip through its second metal segment. The second metal segment and part of the first metal segment of the second signal terminal are covered by the molding compound, while the remaining first metal segment is exposed outside the molding compound.

6. The encapsulated power module structure as described in claim 5, characterized in that, The first signal terminal, the second signal terminal, and the power terminal are all separate entities; or, the first signal terminal is a separate entity, while the second signal terminal and the power terminal are a single unit.

7. The plastic-encapsulated power module structure as described in claim 3, characterized in that, The power chip contains a first electrode, a second electrode, and a third electrode; The second metal segment of the power terminal is connected to the second electrode of the power chip, the first signal terminal is connected to the third electrode of the power chip, and the second signal terminal is connected to the second electrode of the power chip. The first electrode of the power chip is connected to the wiring layer through a first solder layer.

8. The encapsulated power module structure as described in claim 3, characterized in that, The first signal terminal and the second signal terminal are soldered terminals or crimped terminals.

9. The plastic-encapsulated power module structure as described in claim 1, characterized in that, The thickness of the second metal segment of the power terminal is less than 0.5 mm, and the thickness of the first metal segment is greater than 0.7 mm.

10. The encapsulated power module structure as described in claim 7, characterized in that, The first solder layer is sintered silver, solder, or conductive silver paste.

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