Power device chip interconnection structure and power device

Abstract

The utility model belongs to the technical field of semiconductor chips, and relates to a power device chip interconnection structure and a power device, the power device chip interconnection structure comprises a copper-clad ceramic substrate and a chip, the chip is connected on the copper-clad ceramic substrate; the copper-clad ceramic substrate comprises a copper-clad ceramic substrate ceramic layer, and the chip is connected to the first connecting copper layer; and one end of the alloy connecting sheet is connected with the metal electrode area on the upper surface of the chip, and the other end of the alloy connecting sheet is connected with the preset area of the first connecting copper layer of the copper-clad ceramic substrate. After the structure is adopted, the chip has the beneficial effects that the alloy connecting sheet is the copper-molybdenum-copper sheet, and the contact area between the copper-molybdenum-copper sheet and the metal electrode region on the upper surface of the chip is increased, so that the current density on the metal electrode region on the upper surface can be prevented from being excessively concentrated, and the temperature of the metal electrode region on the upper surface is reduced; therefore, the thermal stress between the copper-molybdenum copper sheet and the upper surface metal electrode area is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of semiconductor chips, and in particular relates to a power device chip interconnection structure and a power device. Background Art

[0002] The chip interconnection technology in power devices is generally to connect the metal electrode area on the upper surface of the chip with the copper layer surface on the copper-clad ceramic substrate through ultrasonic bonding wires. The existing wire bonding technology is to connect the thick aluminum wire to the upper surface of the chip and the upper surface of the copper-clad ceramic substrate through ultrasonic bonding process to achieve circuit connection between the chip and the copper-clad ceramic substrate, such as Figure 1 As shown. The diameter of the thick aluminum wire is generally 100-500μm, and multiple metal bonding wires are connected in parallel on a single chip to meet the demand for large current. The disadvantage of this connection technology is that the ultrasonic bonding process is easy to damage the aluminum wire and the chip, and the process requirements are high. In addition, the bonding point area is small, resulting in excessive concentration of current in the metal area on the chip surface, that is, the current flowing through a single bonding point is too high, which will increase the thermal failure phenomenon. At the same time, the bonding points are relatively concentrated, and the temperatures are coupled with each other, further increasing the probability of chip overheating failure.

[0003] When the chip is repeatedly switched on and off, the chip is in a state of repeated heating and cooling, so that the bonding point between the metal bonding wire and the chip is repeatedly affected by stress, causing the metal bonding wire to fall off or break. When one bonding wire fails, the current of the remaining bonding wires increases, and the Joule heat of each wire increases, forming a domino effect, accelerating the failure of the bonding wires and reducing the service life of the power module. Therefore, it is necessary to improve the bonding method. Utility Model Content

[0004] In order to solve the above problems in the prior art, the utility model provides a power device chip interconnection structure and a power device, which improves the heat dissipation effect of the chip, reduces chip damage caused by excessive temperature, and thus increases the service life of the power device.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] As one aspect of the utility model, a power device chip interconnection structure is proposed, which comprises: a copper-clad ceramic substrate and a chip, wherein the chip is connected to the copper-clad ceramic substrate; the copper-clad ceramic substrate comprises a copper-clad ceramic substrate ceramic layer, wherein the copper-clad ceramic substrate ceramic layer has a first surface and a second surface arranged oppositely, wherein a first connection copper layer is connected to the first surface, and a second connection copper layer is connected to the second surface; and the chip is connected to the first connection copper layer;

[0007] It also includes an alloy connecting piece, one end of which is connected to the metal electrode area on the upper surface of the chip, and the other end of the alloy connecting piece is connected to a preset area of ​​the first connecting copper layer of the copper-clad ceramic substrate to form an interconnection structure.

[0008] Optionally, the alloy connecting sheet is in sheet shape.

[0009] Optionally, one end of the alloy connecting piece is connected to the metal electrode area on the upper surface of the chip through the first welding layer, and the other end of the alloy connecting piece is connected to a preset area of ​​the first connecting copper layer of the copper-clad ceramic substrate through the first welding layer.

[0010] Optionally, the alloy connecting sheet is a copper-molybdenum-copper sheet.

[0011] Optionally, the area where the alloy connecting piece is connected to the metal electrode area on the upper surface of the chip is the first connecting portion, and the area where the alloy connecting piece is connected to the first connecting copper layer of the copper-clad ceramic substrate is the second connecting portion.

[0012] Optionally, a bending area is formed on the alloy connecting piece near the second connecting portion, so that the distance between the first connecting portion and the upper surface metal electrode area is the same as the distance between the second connecting portion and the first connecting copper layer.

[0013] Optionally, the thickness of the first connecting portion is smaller than the thickness of the second connecting portion.

[0014] Optionally, a heat sink is further included, wherein the heat sink is connected to the copper-clad ceramic substrate, and the second connecting copper layer of the copper-clad ceramic substrate is connected to the heat sink.

[0015] Optionally, the heat sink and the second connecting copper layer are connected via a second welding layer.

[0016] As another aspect of the utility model, a power device is provided, which includes a housing, wherein the power device chip interconnection structure as described above is connected inside the housing, and wherein the housing is filled with potting glue, and the potting glue covers the power device chip interconnection structure.

[0017] The beneficial effects of the power device chip interconnection structure of the utility model are specifically embodied in that: the alloy connecting sheet is a copper-molybdenum-copper sheet, and the contact area between the copper-molybdenum-copper sheet and the upper surface metal electrode area of ​​the chip is increased, which can avoid excessive concentration of surface current density on the upper surface metal electrode area, reduce the temperature of the upper surface metal electrode area, and thus reduce the thermal stress between the copper-molybdenum-copper sheet and the upper surface metal electrode area, and finally reduce the risk of fatigue fracture of the first welding layer; at the same time, the copper-molybdenum-copper sheet has excellent thermal conductivity, can provide a heat dissipation channel for the chip, is beneficial to reduce the junction temperature of the chip, and can improve the reliability of the solder layer, so the reliability and stability of the power device as a whole can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings in the specification, which constitute a part of the present application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0019] Figure 1 A structural stereogram of a power device chip interconnection structure in the prior art;

[0020] Figure 2 This is a three-dimensional diagram of the first structure of the power device chip interconnection structure of the utility model;

[0021] Figure 3 It is a cross-sectional view of the first structural package of the power device chip interconnection structure of the utility model;

[0022] Figure 4 This is a second structural stereogram of the power device chip interconnection structure of the utility model;

[0023] Figure 5 It is a cross-sectional view of the second structural package of the power device chip interconnection structure of the utility model;

[0024] Figure 6 It is a schematic structural diagram of the upper surface metal electrode area of ​​the utility model. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be clearly and completely described below in combination with the specific embodiments of the utility model and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0026] A power device chip interconnection structure according to an embodiment of the present application is as follows: Figure 2-Figure 6 As shown, it includes: a copper-clad ceramic substrate and a chip 2, the chip 2 is connected to the copper-clad ceramic substrate; the copper-clad ceramic substrate plays the role of flow, insulation, heat conduction and mechanical support; the copper-clad ceramic substrate includes a copper-clad ceramic substrate ceramic layer 4, the copper-clad ceramic substrate ceramic layer 4 has a first surface and a second surface arranged oppositely, the first surface is connected with a first connection copper layer 31, and the second surface is connected with a second connection copper layer 32; the chip 2 is connected to the first connection copper layer 31; the structure of the chip 2 and the connection structure with the copper-clad ceramic substrate are prior art, and will not be repeated here;

[0027] It also includes an alloy connecting sheet 1, which is in sheet shape; one end of the alloy connecting sheet 1 is connected to the metal electrode area 20 on the upper surface of the chip 2 through the first welding layer 12, and the other end of the alloy connecting sheet 1 is connected to a preset area of ​​the first connecting copper layer 31 of the copper-clad ceramic substrate through the first welding layer 12 to form an interconnection structure.

[0028] In one embodiment, the chip 2 is welded to the first connection copper layer 31 of the copper-clad ceramic substrate through a metal sintered layer. The metal sintered layer has good high temperature resistance, good connection reliability in a high temperature environment, and good thermal conductivity.

[0029] In one embodiment, the alloy connecting sheet 1 is a copper-molybdenum-copper (Cu-Mo-Cu) sheet. The contact area between the copper-molybdenum-copper sheet and the upper surface metal electrode area 20 of the chip 2 is increased, which can avoid excessive concentration of surface current density on the upper surface metal electrode area 20, reduce the temperature of the upper surface metal electrode area 20, and thus reduce the thermal stress between the copper-molybdenum-copper sheet and the upper surface metal electrode area 20, and ultimately reduce the risk of fatigue fracture of the first welding layer 12; at the same time, the copper-molybdenum-copper sheet has excellent thermal conductivity and can provide a heat dissipation channel for the chip 2, which is beneficial to reducing the junction temperature of the chip 2 and can improve the reliability of the solder layer, so the overall reliability and stability of the power device can be improved.

[0030] In one embodiment, if Figure 2-Figure 5 As shown, the area where the alloy connecting piece 1 is connected to the upper surface metal electrode area 20 of the chip 2 is the first connecting portion, and the area where the alloy connecting piece 1 is connected to the first connecting copper layer 31 of the copper-clad ceramic substrate is the second connecting portion.

[0031] In one embodiment, if Figure 2 and Figure 3 As shown, the alloy connecting piece 1 is formed with a bending area near the second connecting part, so that the distance between the first connecting part and the upper surface metal electrode area 20 is the same as the distance between the second connecting part and the first connecting copper layer 31, ensuring the consistent printing thickness of the solder layer to meet the process requirements.

[0032] In one embodiment, if Figure 4 and Figure 5 As shown, the thickness of the first connecting part is smaller than that of the second connecting part, so that the distance between the first connecting part and the upper surface metal electrode area 20 is the same as the distance between the second connecting part and the first connecting copper layer 31, ensuring the consistent printing thickness of the solder layer to meet the process requirements, while avoiding the pre-bending process of the alloy connecting sheet 1, reducing the process steps, and improving the product yield.

[0033] In one embodiment, if Figure 3As shown, a heat sink 6 is also included, and the heat sink 6 is connected to the copper-clad ceramic substrate. The second connecting copper layer 32 of the copper-clad ceramic substrate is connected to the heat sink 6. The heat sink 6 plays a role of heat conduction and mechanical support.

[0034] In one embodiment, if Figure 3 As shown, the heat sink 6 and the second connection copper layer 32 are connected via the second welding layer 5 .

[0035] As another aspect of the utility model, a power device is proposed, which includes a shell, in which the power device chip interconnection structure as described above is connected, and the shell is filled with potting glue, which covers the power device chip interconnection structure; the potting glue is epoxy resin or silicone gel.

[0036] In one embodiment, the first welding layer 12 and the second welding layer 5 are both metal sintered layers; the metal sintered layer has good high temperature resistance, good connection reliability in a high temperature environment, and good thermal conductivity, which can not only improve the connection reliability of the packaging structure in a high temperature working environment, but also accelerate the heat conduction of the device and improve the heat dissipation performance.

[0037] In this embodiment, the copper-molybdenum-copper sheet is used to replace the traditional metal bonding wire, and the copper-molybdenum-copper sheet is designed into a standard or irregular shape according to the circuit layout of the copper-clad ceramic substrate. Based on the height difference between the upper surface of the chip and the upper surface of the copper-clad ceramic substrate, one end of the copper-molybdenum-copper sheet is welded to the upper surface metal electrode area of ​​the chip through a sintering process, and the other end is sintered to the upper surface of the copper-clad ceramic substrate through a bending process; or a copper-molybdenum-copper sheet with a certain thickness compensation is welded to the bottom of the first layer of copper-molybdenum-copper sheet to replace the bending process.

[0038] Compared with aluminum wire, copper-molybdenum copper sheet has a lower thermal expansion coefficient, which can reduce the breakage and falling off caused by thermal stress at the lead bonding point, thereby increasing the cycle life of the power device. Secondly, the bonding point area of ​​aluminum wire is small, so the current flowing through the bonding point is more concentrated. Under the action of contact resistance, a large current in a short period of time will cause the bonding point temperature to rise instantly, which will increase the probability of failure of the bonding point due to thermal stress and cause the aluminum wire to fall off. However, copper-molybdenum copper sheet can be cut to a size that matches the area of ​​the metal electrode area on the upper surface of the chip, while reducing the overheating of the traditional bonding point, ensuring the output capacity of large current. Secondly, the thermal conductivity of copper-molybdenum copper sheet is higher than that of aluminum wire, which can improve the heat dissipation effect of the chip, reduce the damage to the chip caused by excessive temperature, and thereby increase the service life of the power device.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0040] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0041] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0042] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0043] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0044] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A power device chip interconnection structure, characterized in that: It includes: A copper-clad ceramic substrate and a chip, wherein the chip is connected to the copper-clad ceramic substrate; the copper-clad ceramic substrate comprises a copper-clad ceramic substrate ceramic layer, wherein the copper-clad ceramic substrate ceramic layer has a first surface and a second surface arranged opposite to each other, wherein a first connection copper layer is connected to the first surface, and a second connection copper layer is connected to the second surface; and the chip is connected to the first connection copper layer; It also includes an alloy connecting piece, one end of which is connected to the metal electrode area on the upper surface of the chip, and the other end of the alloy connecting piece is connected to a preset area of ​​the first connecting copper layer of the copper-clad ceramic substrate to form an interconnection structure; the alloy connecting piece is in sheet shape; the alloy connecting piece is a copper-molybdenum-copper sheet.

2. The power device chip interconnection structure according to claim 1, characterized in that: One end of the alloy connecting piece is connected to the metal electrode area on the upper surface of the chip through the first welding layer, and the other end of the alloy connecting piece is connected to a preset area of ​​the first connecting copper layer of the copper-clad ceramic substrate through the first welding layer.

3. The power device chip interconnection structure according to claim 1, characterized in that: The area where the alloy connecting piece is connected to the metal electrode area on the upper surface of the chip is the first connecting portion, and the area where the alloy connecting piece is connected to the first connecting copper layer of the copper-clad ceramic substrate is the second connecting portion.

4. The power device chip interconnection structure according to claim 3, characterized in that: The alloy connecting piece is formed with a bending area near the second connecting portion, so that the distance between the first connecting portion and the upper surface metal electrode area is the same as the distance between the second connecting portion and the first connecting copper layer.

5. The power device chip interconnection structure according to claim 3, characterized in that: The thickness of the first connection portion is smaller than the thickness of the second connection portion.

6. The power device chip interconnection structure according to any one of claims 1 to 5, characterized in that: It also includes a heat sink, which is connected to the copper-clad ceramic substrate, and the second connecting copper layer of the copper-clad ceramic substrate is connected to the heat sink.

7. The power device chip interconnection structure according to claim 6, characterized in that: The heat sink and the second connecting copper layer are connected via a second welding layer.

8. A power device, characterized in that: It comprises a shell, in which the power device chip interconnection structure according to any one of claims 1 to 7 is connected, and the shell is filled with potting glue, which covers the power device chip interconnection structure.

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