Power Module Pillar-Plate Structure for Stress and Current Uniformity
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Solution Overview
Problem
Existing power modules face challenges in stress accumulation, thermal mismatch, and uneven current distribution, which affect their reliability and heat dissipation efficiency.
Innovation Solution
The power module design incorporates supporting pillars and a metal plate connected by bonding materials, with a substrate featuring a metallic layer and chips, to enhance reliability and current uniformity through stress reduction and improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If supporting pillars and metal plate are added to reduce stress accumulation, then reliability is improved, but device complexity increases
Solution Approach 1:
The substrate is segmented into multiple supporting pillars that are distributed across the substrate surface. Each pillar independently supports the metal plate and distributes stress locally, preventing stress concentration while maintaining overall structural integrity. This segmentation approach improves reliability without requiring a complete redesign of the entire substrate structure.
Solution Approach 2:
The metal plate is positioned at a different vertical dimension (height) above the substrate surface, supported by the pillars. This three-dimensional arrangement allows the metal plate to span across multiple pillars, creating a distributed stress support system that enhances reliability while adding spatial efficiency to the design.
2Reliability
If bonding bodies are positioned right above chips and gap, then current distribution uniformity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The bonding bodies are strategically positioned in different locations: some directly above the chips and others above the gap between chips. This creates local quality variations in the current distribution path, ensuring that current flows uniformly through both the chip regions and the gap regions, thereby improving overall current distribution uniformity.
Solution Approach 2:
The metal plate connected by bonding bodies creates equipotential regions that balance the electrical potential distribution across the chips and gaps. By positioning bonding bodies to connect the metal plate at multiple points, the system achieves equipotential conditions that promote uniform current distribution, reducing hot spots and improving reliability.
3Temperature
If metal plate bends toward metallic layer, then heat dissipation efficiency is improved, but structural stability may be affected
Solution Approach 1:
The metal plate is designed with bending capability, allowing it to dynamically adjust its shape in response to thermal gradients and mechanical stresses. The bending toward the metallic layer creates an optimized thermal conduction path while the flexible design accommodates thermal expansion and contraction, maintaining structural stability under varying operating conditions.
Solution Approach 2:
The metal plate adopts a curved or bent configuration rather than a flat structure. This curvature optimizes the thermal contact area with the metallic layer, improving heat dissipation efficiency. The curved geometry also provides mechanical flexibility to accommodate thermal stresses, preventing structural failure while maintaining intimate thermal contact.
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
The design reduces stress accumulation, enhances reliability, and achieves uniform current distribution and efficient heat dissipation, improving the overall performance of the power module.
Implementation Method 1
The bonding bodies connect the metal plate and the metallic layer
Implementation Method 2
The supporting pillars are on the chips. The metal plate is on the supporting pillars and connected with the supporting pillars
Implementation Method 3
achieves uniform current distribution and efficient heat dissipation
Data Source
AI summary
A power module includes a substrate, chips, supporting pillars, a metal plate and bonding bodies is disclosed. The substrate includes a metallic layer. The chips are on the metallic layer of the substrate, and each of the chips includes a source, a gate, and a drain. The supporting pillars are on the chips. The metal plate is on the supporting pillars and connected with the supporting pillars. The bonding bodies connect the metal plate and the metallic layer.