A plastic-encapsulated power module structure

Abstract

The present invention provides a plastic-encapsulated power module structure, comprising: a substrate, wherein the upper layer of the substrate is a wiring layer, and the lower layer is an insulating layer; a first group of chips and a second group of chips are respectively an upper tube and a lower tube; the upper tube and the lower tube each contain at least one power device; the upper tube contains at least a first pole and a second pole, and the lower tube contains at least a third pole and a fourth pole; the first terminal is connected to the first pole, the second terminal is connected to the fourth pole, and the third terminal is connected to the second pole and the third pole at the same time; the third terminal is led out from a first side surface of the substrate, the second terminal is led out from a second side surface of the substrate, the first side surface is opposite to the second side surface, and the first terminal is led out from an upper surface of the substrate; the positive busbar of the first terminal and the negative busbar of the second terminal are led out in the same direction, so that the positive busbar of the first terminal and the negative busbar of the second terminal have an overlapping part.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a plastic-encapsulated power module structure. Background Art

[0002] Power modules are widely used in new energy vehicles, new energy power generation, smart grids, transportation electrification and other fields. In some fields, such as new energy vehicle controllers, there are higher requirements for miniaturization, lightweight and high power of power modules. In order to achieve high power capabilities, multi-chip parallel connection is often used, but multi-chip parallel connection brings some challenges. The parasitic inductance of the power loop in traditional power modules is large, which leads to voltage overshoot and electromagnetic interference problems, increases switching losses, and reduces device reliability. In addition, the mismatch of branch parameters inside the module may cause unbalanced current in parallel chips, which in turn causes thermal failure of a single chip.

[0003] Infineon's HPD (HybirdPACK Drive) module is a shell-sealed module with silicone filling inside and a half-bridge structure. However, the parasitic inductance is relatively high. Depending on the number of internal parallel chips, the loop parasitic inductance ranges from 8nH to 12nH. For example, the parasitic inductance of the 8-chip parallel version is about 10nH.

[0004] Tesla's T-pak module is a plastic-encapsulated module with high parasitic inductance.

[0005] Therefore, how to reduce the parasitic inductance of the loop inside the module or the parasitic inductance outside the module is the focus of those skilled in the art. Summary of the invention

[0006] The purpose of the present invention is to provide a plastic-encapsulated power module structure, which can at least reduce the parasitic inductance outside the module.

[0007] In order to achieve the above object, the present invention provides a plastic-encapsulated power module structure, comprising:

[0008] A substrate, wherein the first layer of the substrate is a wiring layer, the second layer is an insulating layer, and at least one plastic package body covers the upper surface of the wiring layer;

[0009] The wiring layer includes a first wiring area and a second wiring area;

[0010] A first group of chips and a second group of chips are arranged on the substrate; the first group of chips are upper tubes, and the second group of chips are lower tubes; the upper tubes and the lower tubes each contain at least one power device; the upper tube contains at least a first pole and a second pole, and the lower tube contains at least a third pole and a fourth pole;

[0011] at least three power terminals, namely a first terminal, a second terminal and a third terminal;

[0012] The first terminal is connected to the first pole of the upper tube, the second terminal is connected to the fourth pole of the lower tube, and the third terminal is connected to the second pole of the upper tube and the third pole of the lower tube at the same time;

[0013] The second pole of the upper tube is connected to the second wiring area of ​​the wiring layer through a metal sheet; the first pole of the upper tube is connected to the first wiring area of ​​the wiring layer through a first solder layer, and the third pole of the lower tube is connected to the second wiring area of ​​the wiring layer through the first solder layer;

[0014] The third terminal is led out from the first side surface of the plastic package body, the second terminal is led out from the second side surface of the plastic package body, the first side surface is opposite to the second side surface, and the first terminal is led out from the upper surface of the plastic package body; the direction from the second side surface to the first side surface is defined as the first reference direction;

[0015] The positive busbar of the first terminal and the negative busbar of the second terminal are led out in the same direction, so that the positive busbar of the first terminal and the negative busbar of the second terminal have an overlapping portion.

[0016] In an optional solution, the metal sheet and the second wiring area of ​​the wiring layer have two connecting surfaces, namely the first connecting surface and the second connecting surface. The wiring layer is centrally divided along the first reference direction, and the first connecting surface and the second connecting surface respectively fall in different divided areas; the current flows from the second terminal through the fourth pole to the third pole of the lower tube, and then flows through the second pole to the first pole of the upper tube through the first connecting surface and the second connecting surface respectively, and finally flows to the first terminal.

[0017] In an optional solution, based on the first reference direction, the arrangement order is the second terminal, the lower tube, the first terminal, the upper tube, and the third terminal.

[0018] In an optional solution, based on the first reference direction, the arrangement order is the second terminal, the lower tube, the upper tube, the first terminal, and the third terminal.

[0019] In an optional solution, based on the first reference direction, the arrangement order is the second terminal, the lower tube, the upper tube and the first terminal in parallel, and the third terminal.

[0020] In an optional solution, the first terminal is a conductive block exposed on the upper surface of the plastic package; or the first terminal is a part of the first wiring area of ​​the wiring layer, exposed through a window of the plastic package.

[0021] In an optional solution, the number of the first terminals is 1 or 2 or more.

[0022] In an optional solution, the second electrode is connected to the bottom edge of one side of the metal sheet through a second solder layer, and the bottom edge of the other side of the metal sheet is connected to the second wiring area of ​​the wiring layer through a third solder layer; wherein the metal sheet is an independent metal sheet or the metal sheet is part of the third terminal.

[0023] In an optional solution, the metal sheet is a sheet-shaped metal structure, or a binding wire structure, and the binding wire includes an aluminum wire, an aluminum tape, a copper wire or a copper tape.

[0024] In an optional solution, a metal layer is provided on the other side of the insulating layer of the substrate.

[0025] The beneficial effects of the present invention are:

[0026] The plastic-encapsulated power module structure of the present invention uses a stacked design of the lead-out structure (positive busbar and negative busbar) to allow currents to flow through adjacent conductors in opposite directions, thereby making the total parasitic inductance smaller than the sum of the self-inductances of the positive busbar and the negative busbar, thereby reducing the parasitic inductance outside the module.

[0027] Furthermore, the inner power loop of the plastic-encapsulated power module structure uses a dual-loop (loop 1 and loop 2) layout to reduce the parasitic inductance of the inner loop of the module. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which like reference numerals generally represent like components.

[0029] Figure 1 FIG. 4 is a top view of a plastic-encapsulated power module structure in an embodiment of the present invention.

[0030] Figure 2 FIG. 4 is a cross-sectional view of a plastic-encapsulated power module structure in an embodiment of the present invention.

[0031] Figure 3 FIG. 4 is a top view of a plastic-encapsulated power module structure in another embodiment of the present invention.

[0032] Figure 4 A top view of a plastic-encapsulated power module structure in another embodiment of the present invention

[0033] Figure 5 FIG. 4 is a top view of a plastic-encapsulated power module structure in another embodiment of the present invention.

[0034] Figure 6 for Figure 2 A partial enlarged view of .

[0035] Figure 7 This is a dual-loop route map according to an embodiment of the present invention.

[0036] Figure 8 This is a positional relationship diagram of the positive busbar of the first terminal and the negative busbar of the second terminal in one embodiment of the present invention.

[0037] Fig. 9 FIG. 4 is a circuit diagram of a first terminal, a second terminal, and a third terminal in an embodiment of the present invention.

[0038] Reference numerals:

[0039] 1-first terminal; 2-second terminal; 3-third terminal; 4-upper tube; 5-lower tube; 6-metal sheet; 7-wiring layer; 8-first solder layer; 9-second solder layer; 10-third solder layer; 11-upper tube signal terminal; 12-lower tube signal terminal; 13-substrate; 14-plastic package; 15-positive busbar of the first terminal; 16-negative busbar of the second terminal. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description and drawings, the advantages and features of the present invention will become clearer. However, it should be noted that the concept of the technical solution of the present invention can be implemented in a variety of different forms and is not limited to the specific embodiments described herein. The drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0041] It should be understood that when an element or layer is referred to as being "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. In contrast, when an element is referred to as being "directly on, directly adjacent to, directly connected to or directly coupled to other elements or layers, there may be 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, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below may be represented as a second element, component, region, layer or part.

[0042] Spatially relative terms such as "under," "below," "below," "under," "above," "above," etc., may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatially relative terms are intended to include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "on" the other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0043] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0044] Example 1

[0045] Reference Figures 1 to 8 This embodiment provides a plastic-encapsulated power module structure, including

[0046] A substrate 13, wherein the first layer of the substrate 13 is a wiring layer 7, the second layer is an insulating layer, and at least one plastic package 14 covers the upper surface of the wiring layer 7; the insulating layer can be made of insulating materials such as aluminum oxide, aluminum nitride, zirconium oxide, silicon nitride, epoxy resin, and silicone;

[0047] The wiring layer 7 includes a first wiring area and a second wiring area;

[0048] The first group of chips and the second group of chips are arranged on the substrate 13; the first group of chips are upper tubes 4 (which can be one power device or multiple power devices), and the second group of chips are lower tubes 5 (which can be one power device or multiple power devices); the power device can be a diode chip (Diode chip), a metal oxide semiconductor field effect transistor chip (MOSFET chip), an insulated gate bipolar transistor chip (IGBT chip), a high electron mobility transistor chip (HEMT chip), a junction field effect transistor chip (JFET chip), a bipolar junction transistor chip (BJT chip) or a thyristor chip (SCR chip); the upper tube 4 at least contains a first electrode and a second electrode, and the lower tube 5 at least contains a third electrode and a fourth electrode; when the power device is a MOSFET chip, the first electrode is a drain electrode, the second electrode is a source electrode, the third electrode is a drain electrode, and the fourth electrode is a source electrode;

[0049] Reference Fig. 9 , at least three power terminals, namely a first terminal 1 (DC+), a second terminal 2 (DC-) and a third terminal 3 (AC);

[0050] The first terminal 1 is connected to the first pole of the upper tube 4, the second terminal 2 is connected to the fourth pole of the lower tube 5, and the third terminal 3 is simultaneously connected to the second pole of the upper tube 4 and the third pole of the lower tube 5;

[0051] The second pole of the upper tube 4 is connected to the second wiring area of ​​the wiring layer 7 through a metal sheet; the first pole of the upper tube 4 is connected to the first wiring area of ​​the wiring layer 7 through a first solder layer 8, and the third pole of the lower tube 5 is connected to the second wiring area of ​​the wiring layer 7 through a first solder layer 8; the first solder layer 8 can be a conductive material such as sintered silver, solder, conductive silver glue, etc.

[0052] The third terminal 3 is led out from the first side surface of the plastic package body 14, the second terminal 2 is led out from the second side surface of the plastic package body 14, the first side surface is opposite to the second side surface, and the first terminal 1 is led out from the upper surface of the plastic package body 14; the direction from the second side surface to the first side surface is defined as a first reference direction;

[0053] Reference Figure 8 The positive busbar 15 of the first terminal and the negative busbar 16 of the second terminal are led out in the same direction, so that the positive busbar 15 of the first terminal and the negative busbar 16 of the second terminal have an overlapping portion.

[0054] In this embodiment, the total parasitic inductance of the module external loop is , L DC+ is the self-inductance of the positive busbar 15 of the first terminal, L DC-is the self-inductance of the negative busbar 16 of the second terminal, and M is the mutual inductance of the positive busbar 15 and the negative busbar 16, which is a positive number. Through the stacking design of the lead-out structure (positive busbar, negative busbar), the current flows through the adjacent conductors in opposite directions, which can make the total parasitic inductance smaller than the sum of the self-inductance of the positive busbar 15 and the negative busbar 16, thereby reducing the parasitic inductance outside the module.

[0055] Specifically, refer to Figure 1 and Figure 7 In this embodiment, based on the first reference direction (from bottom to top), the arrangement order is the second terminal 2, the lower tube 5, the first terminal 1, the upper tube 4, and the third terminal 3. The metal sheet 6 and the second wiring area of ​​the wiring layer have two connection surfaces, namely the first connection surface and the second connection surface. The wiring layer is centrally divided in the first reference direction, and the first connection surface and the second connection surface fall in different divided areas. The current flows from the second terminal 2 through the fourth pole of the lower tube 5 to the third pole, and then flows through the second pole of the upper tube 4 to the first pole through the first connection surface and the second connection surface (the dotted boxes distributed on the left and right), and finally flows to the first terminal 1.

[0056] The power circuit in the plastic-encapsulated power module structure uses a dual-loop (loop1 and loop2) layout to reduce the parasitic inductance of the module's internal loop. The total parasitic inductance of the module's internal loop is According to the arithmetic inequality, we know Therefore, the dual-circuit arrangement can greatly reduce the parasitic inductance of the circuit inside the module.

[0057] Reference Figure 3 In another embodiment, based on the first reference direction, the arrangement order is the second terminal 2, the lower tube 5, the upper tube 4, the first terminal 1, and the third terminal 3.

[0058] Reference Figure 4 In another embodiment, based on the first reference direction, the arrangement order is the second terminal 2, the lower tube 5, the upper tube 4 parallel to the first terminal 1, and the third terminal 3.

[0059] In this embodiment, the first terminal 1 is a conductive block, which is exposed on the upper surface of the plastic package. In another embodiment, the first terminal 1 is a part of the wiring layer, which is exposed through a window of the plastic package. The conductive block can be made of conductive materials such as copper, aluminum, copper-molybdenum alloy, aluminum silicon carbide, etc.

[0060] Reference Figure 4 , the number of the first terminal is 1. Figure 5, the number of first terminals 1 is 2, and in other embodiments, the number of first terminals can be more than one. The internal power circuit of the power module of this embodiment is also a dual-circuit structure, and the connection surface between the metal sheet 6 and the second wiring area of ​​the wiring layer is one (located between the two first terminals 1), and the wiring layer is centrally divided in the first reference direction. The current flows from the second terminal 2 through the fourth pole of the lower tube 5 to the third pole, and then flows through the metal sheet 6 through the second pole of the upper tube 4 to the first pole, and finally flows to the two first terminals 1 in two ways.

[0061] In this embodiment, the second electrode is connected to one side bottom edge of the metal sheet 6 through the second solder layer 9, and the other side bottom edge of the metal sheet 6 is connected to the second wiring area of ​​the wiring layer 7 through the third solder layer 10, wherein the metal sheet 6 can be an independent metal sheet or the metal sheet 6 is a part of the third terminal 3. The metal sheet 6 can be a sheet-like metal structure, or a binding wire structure, and the binding wire includes aluminum wire, aluminum strip, copper wire or copper strip. The second solder layer 9 and the third solder layer 10 can be conductive materials such as sintered silver, solder, conductive silver glue, etc.

[0062] In this embodiment, the plastic-encapsulated power module structure also includes an upper tube signal terminal 11 and a lower tube signal terminal 12. The two signal terminals can be welding terminals or press-fit terminals located on the side of the module, or welding terminals, press-fit terminals, bosses, windows, etc. located on the upper surface of the module.

[0063] In this embodiment, a metal layer is provided on the other side of the insulating layer of the substrate 13 (the side opposite to the wiring layer 7 ), and the metal layer can be used for heat conduction or electrical connection.

[0064] The power module of this embodiment greatly reduces the parasitic inductance of parallel chips through the low inductance design both inside and outside the module, while achieving better current sharing characteristics, thereby improving the reliability of the module.

[0065] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection 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 plastic package body covers the upper surface of the wiring layer; The wiring layer includes a first wiring area and a second wiring area; A first group of chips and a second group of chips are arranged on the substrate; the first group of chips are upper tubes, and the second group of chips are lower tubes; the upper tubes and the lower tubes each contain at least one power device; the upper tube contains at least a first pole and a second pole, and the lower tube contains at least a third pole and a fourth pole; at least three power terminals, namely a first terminal, a second terminal and a third terminal; The first terminal is connected to the first pole of the upper tube, the second terminal is connected to the fourth pole of the lower tube, and the third terminal is connected to the second pole of the upper tube and the third pole of the lower tube at the same time; The second pole of the upper tube is connected to the second wiring area of ​​the wiring layer through a metal sheet; the first pole of the upper tube is connected to the first wiring area of ​​the wiring layer through a first solder layer, and the third pole of the lower tube is connected to the second wiring area of ​​the wiring layer through the first solder layer; The third terminal is led out from the first side surface of the plastic package body, the second terminal is led out from the second side surface of the plastic package body, the first side surface is opposite to the second side surface, and the first terminal is led out from the upper surface of the plastic package body; defining a direction from the second side surface to the first side surface as a first reference direction; The positive busbar of the first terminal and the negative busbar of the second terminal are led out in the same direction, so that the positive busbar of the first terminal and the negative busbar of the second terminal have an overlapping portion; The metal sheet and the second wiring area of ​​the wiring layer have two connection surfaces, namely a first connection surface and a second connection surface, and the wiring layer is centrally divided along the first reference direction, and the first connection surface and the second connection surface fall in different divided areas respectively; The current flows from the second terminal through the fourth pole of the lower tube to the third pole, and then respectively flows through the second pole of the upper tube to the first pole through the first connection surface and the second connection surface, and finally flows to the first terminal.

2. The plastic-encapsulated power module structure according to claim 1, characterized in that: Based on the first reference direction, the arrangement order is the second terminal, the lower tube, the first terminal, the upper tube, and the third terminal.

3. The plastic-encapsulated power module structure according to claim 1, characterized in that: Based on the first reference direction, the arrangement order is the second terminal, the lower tube, the upper tube, the first terminal, and the third terminal.

4. The plastic-encapsulated power module structure according to claim 1, characterized in that: Based on the first reference direction, the arrangement order is the second terminal, the lower tube, the upper tube and the first terminal in parallel, and the third terminal.

5. The plastic-encapsulated power module structure according to claim 1, characterized in that: The first terminal is a conductive block, exposed on the upper surface of the plastic package; or the first terminal is a part of the first wiring area of ​​the wiring layer, exposed through a window of the plastic package.

6. The plastic-encapsulated power module structure according to claim 1, characterized in that: The number of the first terminals is 1 or 2 or more.

7. The plastic-encapsulated power module structure according to claim 1, characterized in that: The second electrode is connected to one bottom edge of the metal sheet through a second solder layer, and the other bottom edge of the metal sheet is connected to the second wiring area of ​​the wiring layer through a third solder layer; wherein the metal sheet is an independent metal sheet or the metal sheet is part of the third terminal.

8. The plastic-encapsulated power module structure according to claim 1, characterized in that: The metal sheet is a sheet-shaped metal structure, or a binding wire structure, and the binding wire includes an aluminum wire, an aluminum strip, a copper wire or a copper strip.

9. The plastic-encapsulated power module structure according to claim 1, characterized in that: A metal layer is disposed on the other side of the insulating layer of the substrate.

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