阅读说明：本技术 功率模块塑封结构 (Power module plastic package structure ) 是由 梁小广 丁烜明 于 2020-08-13 设计创作，主要内容包括：本发明提供了一种功率模块塑封结构,包括：金属底板、环氧树脂层以及支撑件；所述金属底板贴附连接在功率模块的底面,所述环氧树脂层包裹所述功率模块,共同将所述功率模块密封在内；所述支撑件设置于所述环氧树脂层内,一端支撑所述功率模块基板的顶面,另一端位于所述环氧树脂层的顶面。通过支撑件的使用,避免环氧树脂在Tg温度之上承受较大压力而引起模块的变形或者损坏。(The invention provides a plastic package structure of a power module, which comprises: the metal base plate, the epoxy resin layer and the supporting piece; the metal bottom plate is attached to the bottom surface of the power module, and the epoxy resin layer wraps the power module and seals the power module together; the support member is arranged in the epoxy resin layer, one end of the support member supports the top surface of the power module substrate, and the other end of the support member is positioned on the top surface of the epoxy resin layer. Through the use of the support, the epoxy resin is prevented from bearing high pressure above the Tg temperature to cause deformation or damage to the module.)

1. A power module plastic envelope structure which characterized in that includes: the metal base plate, the epoxy resin layer and the supporting piece;

the metal bottom plate is attached to the bottom surface of the power module, and the epoxy resin layer wraps the power module and seals the power module together;

the support member is arranged in the epoxy resin layer, one end of the support member supports the top surface of the power module substrate, and the other end of the support member is positioned on the top surface of the epoxy resin layer.

2. The plastic package structure of power module according to claim 1, wherein the supporting member is perpendicular to the power module.

3. The power module plastic package structure of claim 1, wherein the other end of the support member is flush with a top surface of the epoxy layer.

4. The plastic package structure of power module according to claim 1, wherein the support member comprises a metal member or an engineering plastic member.

5. The plastic package structure of the power module according to claim 1, wherein the power module comprises a terminal, and one end of the terminal is exposed through the epoxy resin layer.

6. The plastic package structure of power module according to claim 1, wherein the power module comprises a terminal, the supporting member comprises a conductive member, the conductive member replaces the terminal of the power module, one end of the conductive member is connected to the terminal connection position of the power module, and the other end of the conductive member is located on the top surface of the epoxy resin layer.

7. The plastic package structure of power module according to claim 6, wherein the conductive member comprises a metal member.

8. The power module plastic package structure of claim 7, wherein the metal piece comprises copper.

Technical Field

The invention relates to the field of semiconductor devices, in particular to a plastic package structure of a power module.

Background

In power supply and power electronic converter applications, power semiconductor (IGBT, MOSFET, SiC, GaN, etc.) devices are widely used, and module packaging is generally used in high power applications. As shown in fig. 1, a package form widely used at present is a power module mainly composed of a metal base plate, a solder layer, a DBC (double-sided copper-clad ceramic substrate), an AMB (foil-soldered copper-clad ceramic substrate), an insulating heat-dissipating resin film or other insulating heat-dissipating material, a bonding wire, a terminal for electrical connection, an epoxy resin, and the like. The power semiconductor chip is fixed to the insulating and heat dissipating material by soldering, and then electrically connected to the insulating and heat dissipating material by an aluminum bonding wire. And then, other insulating heat dissipation materials of the DBC are welded on the metal base plate through processes of reflow soldering, sintering and the like, heat emitted by the power semiconductor wafer is conducted to the metal base plate through the DBC or other insulating heat dissipation materials and the welding layer, the metal base plate is cooled by air cooling or water cooling, and the terminal is used for being connected with an external electric circuit.

Fig. 2 is an example of a Transfer molding packaging process in which an epoxy resin heated to a liquid state is injected into an injection mold by high pressure to form an injection molding power module together with other devices.

Fig. 3 is an example of a Compression molding process, where the first step secures the components of the power module to the upper mold of the Compression mold. In the second step, the epoxy resin in the lower mold is fused into a liquid. And thirdly, pushing the lower die to the upper die, completely immersing the components of the power module into the epoxy resin, and simultaneously vacuumizing to remove air bubbles in the epoxy resin. And fourthly, finishing the packaging after the epoxy resin is hardened.

Since the power module generates a large amount of heat, it needs to dissipate the heat through a metal heat sink and a metal heat sink (copper or aluminum), and a conventional silicone grease (silicon grease) is used to connect the module and the metal heat sink, as shown in fig. 4. The silicone grease fills up the fine uneven part of the surface of the metal radiator, so that the module is more attached to the radiator. However, the thermal conductivity of the silicone grease material is low (< 10W), which affects the heat dissipation capability of the system.

In order to improve the heat dissipation capacity, the heat conductivity coefficient of the sintering material (such as silver sintering material and copper sintering material) can reach more than 200W, and the sintering material can be used as a substitute of silicone grease, so that the heat dissipation capacity of the module is greatly improved. However, the sintering material needs to form an effective sintering layer at a high temperature of 250 ℃ or higher and a pressure of 10MPa to 30 MPa. To reduce the processing time (the lower the temperature, the longer the time to process) the 280 to 300 c is often selected for pressing. Epoxy resin materials used for the molding module generally have a Tg (glass transition temperature) of 200 ℃ or less, and recently, materials having a Tg of 250 ℃ have appeared, but they are expensive and lower than the temperature required for sintering. Because the sintering temperature is higher than the Tg of the epoxy resin, the epoxy resin may become insufficiently strong to withstand high pressures during the sintering process, causing deformation or damage to the module.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a plastic package structure of a power module.

According to the invention, the power module plastic package structure provided comprises: the metal base plate, the epoxy resin layer and the supporting piece;

the metal bottom plate is attached to the bottom surface of the power module, and the epoxy resin layer wraps the power module and seals the power module together;

the support member is arranged in the epoxy resin layer, one end of the support member supports the top surface of the power module substrate, and the other end of the support member is positioned on the top surface of the epoxy resin layer.

Preferably, the support and the power module are perpendicular to each other.

Preferably, the other end of the support member is flush with a top surface of the epoxy layer.

Preferably, the support comprises a metal piece or an engineered plastic piece.

Preferably, the power module includes a terminal, one end of which is exposed to the outside through the epoxy resin layer.

Preferably, the power module includes a terminal, and the supporter includes a conductive member instead of the terminal of the power module, one end of the conductive member being connected to a terminal connection position of the power module, and the other end thereof being located on a top surface of the epoxy layer.

Preferably, the conductive member includes a metal member.

Preferably, the metal piece comprises copper.

Compared with the prior art, the invention has the following beneficial effects:

through the use of the support, the epoxy resin is prevented from bearing high pressure above the Tg temperature to cause deformation or damage to the module.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

fig. 1 is a schematic structural diagram of a conventional power module;

FIG. 2 is a schematic view of a compression molding and plastic packaging process;

FIG. 3 is a schematic view of a compression molding process;

FIG. 4 is a schematic diagram of the connection between the power module and the heat sink;

fig. 5 is a schematic structural diagram of a plastic package structure of a power module according to the present invention;

fig. 6 is a schematic structural diagram of another power module plastic package structure according to the present invention.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.