Vertically Aligned Power Module Layout for Lower Thermal Coupling
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Solution Overview
Problem
Conventional power modules with SiC transistor dies suffer from suboptimal thermal performance due to strong thermal coupling and inefficient heat dissipation, especially in fully populated designs, where the top die carrier substrate contributes only about 30% to total heat dissipation.
Innovation Solution
A power module design featuring vertically aligned substrates with patterned metallizations, where high-side and low-side vertical power transistor dies are attached to different substrates, allowing for thermally decoupled heat dissipation through separate sides, and utilizing spacers for electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If SiC transistor dies are used to implement half bridge switches, then voltage operation, temperature ranges, and switching frequencies are improved, but thermal performance deteriorates due to strong thermal coupling between dies
Solution Approach 1:
The patent transitions from a conventional planar arrangement of power transistor dies to a three-dimensional stacked configuration where high-side and low-side dies are vertically separated onto different substrates. This dimensional change increases the thermal distance between heat-generating dies, reducing thermal coupling while maintaining electrical functionality through vertical interconnects.
Solution Approach 2:
The power module is segmented into multiple substrates (top and bottom substrates) with dies distributed across these separate layers. High-side switches are mounted on one substrate while low-side switches are mounted on another, physically separating heat sources and enabling independent thermal management for each substrate.
2Ease of manufacture
If the top die carrier substrate is used for mounting dies, then electrical connections are simplified, but thermal performance deteriorates because only about 30% of total heat dissipation is achieved
Solution Approach 1:
The invention utilizes the vertical dimension by mounting dies on both the top and bottom substrates rather than concentrating all dies on a single top substrate. This enables heat dissipation from both the top and bottom surfaces of the module, effectively doubling the available cooling area and improving overall thermal performance.
Solution Approach 2:
The patent combines the functions of multiple substrates (top and bottom) into a unified thermal management system where both substrates actively participate in heat dissipation. The metallization layers on both substrates are designed to serve as thermal pathways, merging their heat dissipation capabilities to achieve superior thermal performance compared to using only the top substrate.
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 thermal performance by optimizing heat dissipation through dual-sided cooling, effectively utilizing the entire substrate area and reducing thermal coupling between high-side and low-side dies.
Implementation Method 1
a source pad electrically connected to a first island of the patterned second metallization via a first plurality of spacers
Implementation Method 2
dual-sided cooling, effectively utilizing the entire substrate area and reducing thermal coupling between high-side and low-side dies
Data Source
AI summary
A power module includes: a first substrate having a patterned first metallization; a second substrate vertically aligned with the first substrate and having a patterned second metallization that faces the patterned first metallization; first vertical power transistor dies having a drain pad attached to a first island of the patterned first metallization and a source pad electrically connected to a first island of the patterned second metallization via first spacers; and second vertical power transistor dies having a source pad electrically connected to the first island of the patterned first metallization via second spacers. A first subset of the second vertical power transistor dies has a drain pad attached to a second island of the patterned second metallization. A second subset of the second vertical power transistor dies has a drain pad attached to a third island of the patterned second metallization. A method of producing the module is described.