Curvature-free substrate used for power IGBT module encapsulation

Abstract

The invention discloses a curvature-free substrate used for power IGBT module encapsulation. The curvature-free substrate used for power IGBT module encapsulation comprises a substrate body, wherein a plurality of convex platforms are arranged on the welding surface of the substrate body, the heat dissipation surface of the substrate body is a plane, and the platforms are more prone to deformation than the substrate body under the action of stress. The curvature-free substrate used for power IGBT module encapsulation has the advantages of being simple and compact in structure, low in cost, easy to manufacture, capable of improving the reliability of an IGBT module and the like.

Description

technical field [0001] The invention mainly relates to the packaging design field of power modules, in particular to a non-curvature substrate used for power IGBT module packaging. Background technique [0002] At present, the packaging design structure and process of power IGBT modules are mainly based on welding methods. In this method, the chip 1 is generally welded to the insulating ceramic liner 2 first, and then the insulating ceramic liner 2 with the chip 1 and the substrate 3 are welded together, such as figure 1 shown. The substrate 3 mainly plays the role of support and heat dissipation in the IGBT module. In many cases, the material of the substrate 3 is AlSiC, and the thermal expansion coefficient difference between this material and the ceramic liner 2 is relatively large. Therefore, there is a relatively large stress in the welding layer 4 between the liner 2 and the AlSiC substrate 3 after welding, and this stress will act on the AlSiC substrate 3, thereby ...

AI Technical Summary

Problems solved by technology

Due to the uncertainty of the deformation of the AlSiC substrate 3, there will always be IGBT modules that are scrapped because the curvature of the substrate 3 does not meet the requirements, resulting in a decrease in packaging yield

[0008] (3) When the IGBT module packaged with a curved AlSiC substrate 3 is installed with the heat sink 5, the high point of the curved surface of the substrate 3 is in close contact with the heat sink 5. Due to the influence of the curvature, the surroundings will be lifted upwards to leave a gap. It is necessary to apply a fastening force through the mounting fastening screws 6 around the substrate 3 to keep it in good contact with the heat sink, but the shape of the curved surface of the AlSiC substrate 3 cannot maintain an ideal state (symmetrical distribution of the center of the concentric circles), so even if the substrate 3 is leveled, there are still bad contact points, which reduces the cooling effect

On the other hand, applying fastening force to flatten the substrate 3 by installing the fastening screws 6 will cause stress inside the IGBT module, which will adversely affect the reliability of the IGBT module.

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