Segmented Multilayer Substrate for Stress and Blind-Hole Control
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Solution Overview
Problem
Multilayer substrates like DBC substrates experience significant stress and strain due to differing thermal expansion coefficients, leading to reduced reliability and robustness, while transfer molding results in blind holes that can cause leakage or abnormal discharge.
Innovation Solution
A multilayer substrate design with segmented insulating material layers and metal layers, featuring openings and notches that match clamping tools for stable fixation, reducing stress and strain, and preventing resin overflow during encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If transfer molding is used to encapsulate power modules, then the molding process can be completed, but blind holes are formed causing leakage or abnormal discharge
Solution Approach 1:
The substrate is divided into multiple segments (first substrate segment, second substrate segment, third substrate segment) with through holes penetrating through all segments. This segmentation allows resin to flow through the entire structure via the through holes and communication channels, eliminating blind holes and preventing leakage while maintaining manufacturing feasibility.
2Device complexity
If conventional DBC substrates are used with continuous insulating material layers, then the substrate structure is simple, but stress and strain are significant due to different CTE between metal layers and insulating material
Solution Approach 1:
The insulating material layer is segmented into multiple separate substrate segments with gaps between them. These segments are connected through through holes and communication channels that allow resin flow. The segmentation reduces thermal stress by creating expansion joints while the resin-filled channels maintain structural integrity and electrical insulation.
Solution Approach 2:
Resin is introduced as an intermediary material that fills the through holes and communication channels between substrate segments. The resin acts as a stress-absorbing medium that accommodates thermal expansion differences between metal layers and insulating material, reducing overall stress and strain while maintaining structural continuity.
3Manufacturing precision
If retract pin is used to prevent resin swirling and overflow, then resin control during molding is improved, but blind holes are inevitably left after resin curing
Solution Approach 1:
Instead of using a retract pin that creates blind holes, the substrate is segmented into multiple parts with through holes penetrating through all segments. This allows resin to flow continuously through the structure without leaving voids, eliminating the harmful effect of blind holes while maintaining precise resin control during molding.
Solution Approach 2:
Rather than using a retract pin to control resin and accepting blind holes as a necessary byproduct, the invention inverts the approach by designing through holes and communication channels that enable complete resin penetration. The structure is designed to guide resin flow through the entire assembly, turning the potential problem of resin overflow into a solution for eliminating blind holes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the reliability and durability of power modules by stabilizing the substrate during molding, eliminating blind holes, and ensuring secure electrical connections.
Implementation Method 1
The first metal layer and the second metal layer are attached to the insulating material layer by sintering, brazing, soldering or curing.
Implementation Method 2
The first metal layer and the second metal layer are attached to the insulating material layer by sintering, brazing, soldering or curing.
Implementation Method 3
The first metal layer and the second metal layer are attached to the insulating material layer by sintering, brazing, soldering or curing.
Data Source
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AI summary
The present disclosure relates to a multilayer substrate, a power module, and an electrical system. A multilayer substrate is provided that comprises: an insulating material layer including a ceramic material; a first metal layer attached to the insulating material layer on a side of the insulating material layer; and a second metal layer attached to the insulating material layer on an opposite side of the insulating material layer, wherein the insulating material layer is configured as a plurality of segments separated from each other, a first portion of the second metal layer, for attaching a chip thereon, overlapping at least one segment of the insulating material layer.