Double-Side Cooled Power Modules With Triple-Point Field Grading
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Solution Overview
Problem
Medium-voltage power modules face challenges with high electric field intensity at triple points, leading to partial discharge and dielectric fatigue, which existing strategies like modifying geometries or using particle-filled polymer composites have not effectively addressed, especially under direct current and pulse width modulation excitations.
Innovation Solution
The use of insulated metal substrates with thin alumina layers and resistive polymer-nanoparticle composite coatings at triple points to reduce electric field stress, combined with sintered-silver interconnections and double-side cooling for improved thermal and electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thickness of the insulating layer is reduced to improve thermal performance, then thermal resistance decreases, but electric field intensity increases leading to partial discharge and dielectric fatigue
Solution Approach 1:
The patent applies different properties to different locations: the insulating layer has uniform thickness for thermal management, while triple points receive additional resistive polymer-nanoparticle composite coatings to locally reduce electric field stress. This local enhancement at critical points allows thin insulating layers without compromising overall dielectric reliability.
Solution Approach 2:
The patent uses composite materials at triple points by coating with resistive polymer-nanoparticle composites. These composite coatings have intermediate conductivity between metals and insulators, creating field-grading effects that reduce electric field intensity at triple points while allowing the bulk insulating layer to remain thin for optimal thermal performance.
2Reliability
If conventional wire-bonded structures are replaced with planar structures to reduce package parasitic inductances, then electrical performance improves, but thermal management challenges increase due to higher power density
Solution Approach 1:
The patent transitions from planar (2D) cooling to three-dimensional (3D) double-side cooling. By utilizing both top and bottom surfaces of the power module for heat dissipation, the system effectively adds a vertical dimension to thermal management, doubling the available heat dissipation area and capacity.
Solution Approach 2:
The patent segments the cooling function by implementing independent cooling paths on both sides of the module. Each side can be optimized for specific thermal loads, with separate heat sinks and cooling channels, allowing differentiated thermal management for different power device regions.
3Reliability
If the insulating layer thickness is increased to improve electrical insulation, then dielectric strength increases, but thermal resistance increases reducing power density
Solution Approach 1:
Instead of uniformly increasing insulating layer thickness throughout the module, the patent applies localized field-grading coatings only at triple points where electric field stress is concentrated. This selective approach maintains thin insulating layers in most areas for optimal thermal and power density performance while providing enhanced insulation precisely where needed.
Solution Approach 2:
The patent changes the electrical parameters at triple points by introducing resistive polymer-nanoparticle composite coatings with intermediate conductivity. This parameter modification creates a gradual field transition zone that increases effective dielectric strength at critical points without requiring increased insulating layer thickness, thereby maintaining high power density.
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
This solution increases partial discharge inception voltage, reduces thermal resistance, and enhances the reliability of power modules by effectively managing heat dissipation and insulation, while maintaining good electrical insulation and thermal performance.
Implementation Method 1
sintered-silver interconnections between the semiconductor device die and the two metal spacers
Implementation Method 2
sintered-silver interconnections between the semiconductor device die and the two metal spacers
Implementation Method 3
double-side cooling for improved thermal and electrical performance
Implementation Method 4
reduces thermal resistance, and enhances the reliability of power modules by effectively managing heat dissipation
Implementation Method 5
resistive polymer-nanoparticle composite coatings at triple points to reduce electric field stress
Implementation Method 6
increases partial discharge inception voltage, reduces thermal resistance, and enhances the reliability of power modules by effectively managing heat dissipation and insulation
Data Source
AI summary
Multi-chip module packaging technologies for GaN and other devices are described. The power module packaging technology described can be applied to all types of medium-voltage devices, such as silicon (Si), silicon carbide (SiC), gallium nitride (GaN), or the latest gallium oxide (Ga2O3) devices. In one example, a power module includes a first substrate, a second substrate, a sintered-silver semiconductor die pillar, the pillar being positioned between the first substrate and the second substrate, a terminal on a first side of the power module, and a terminal on a second side of the power module.