Power Module Substrate Layout for Low Inductance and Warping Control
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Solution Overview
Problem
Existing power module substrates experience increased parasitic inductance and deformation due to thermal stress and magnetic flux interference, which are not effectively addressed by current designs.
Innovation Solution
A substrate design featuring front and rear surface patterns on an insulation sheet, with overlapping configurations to balance thermal stress and magnetic flux, and a connection pattern to electrically connect rear surface patterns, reducing parasitic inductance and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the second plate layer is divided by grooves to reduce warping caused by thermal stress, then thermal stress-induced deformation is reduced, but the path of overcurrent is blocked and parasitic inductance increases
Solution Approach 1:
The second plate layer is divided into multiple isolated patterns (first, second, and third patterns) separated by grooves. This segmentation reduces thermal stress-induced warping by allowing independent thermal expansion of each pattern while maintaining electrical connectivity through the insulation sheet to achieve magnetic flux cancellation and reduce parasitic inductance
Solution Approach 2:
The insulation sheet serves as an intermediary that electrically connects the isolated second plate patterns. It provides both electrical insulation for thermal management and electrical conductivity for current flow, enabling the patterns to be electrically connected while remaining physically isolated to reduce thermal stress
2Reliability
If the second plate layer is made as a single continuous layer to provide smooth current path, then parasitic inductance is reduced, but thermal stress causes warping and deformation of the module
Solution Approach 1:
The second plate layer is divided into multiple isolated patterns (first, second, and third patterns) separated by grooves. This segmentation reduces thermal stress-induced warping by allowing independent thermal expansion of each pattern while maintaining electrical connectivity through the insulation sheet to achieve magnetic flux cancellation and reduce parasitic inductance
Solution Approach 2:
Multiple isolated second plate patterns are electrically merged through the insulation sheet to function as a unified current path. The patterns are positioned to cancel magnetic flux effectively, achieving low parasitic inductance while remaining physically segmented to manage thermal stress
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 effectively reduces parasitic inductance and prevents substrate deformation by balancing thermal stress and managing magnetic flux, enhancing power conversion efficiency and durability.
Implementation Method 1
the plurality of rear surface patterns are formed so that thermal stress acting on the plurality of rear surface patterns and thermal stress acting on the plurality of front surface patterns are balanced
Implementation Method 2
a magnetic flux of the current flowing through the first plate layer and a magnetic flux of the overcurrent flowing through the second plate layer may not cancel each other out smoothly in some cases. As a result, parasitic inductance may increase
Data Source
AI summary
A substrate for a power module of the present disclosure includes: an insulation sheet; a plurality of front surface patterns formed on a front surface of the insulation sheet and disposed adjacent to each other with a gap between the plurality of front surface patterns in a direction in which the insulation sheet expands; a power semiconductor element connected to the front surface pattern; a plurality of rear surface patterns formed on a rear surface of the insulation sheet and disposed adjacent to each other with a gap between the plurality of rear surface patterns in the direction in which the insulation sheet expands; and a connection pattern disposed in the gap to fill the rear surface in the gap between the neighboring rear surface patterns of the plurality of rear surface patterns and configured to electrically connect the neighboring rear surface patterns, wherein each of the rear surface patterns and at least one front surface pattern overlap with the insulation sheet disposed therebetween in a direction perpendicular to the insulation sheet, and the plurality of rear surface patterns are formed so that thermal stress acting on the plurality of rear surface patterns and thermal stress acting on the plurality of front surface patterns are balanced.