Power Electronics Assembly With Thick Metallization Heat Spreading

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Solution Overview

Problem

Current power electronic assemblies face challenges in efficiently distributing heat due to significant temperature differences between switching components and cooler regions, leading to complex cooler designs and reduced thermal management efficiency.

Innovation Solution

A power electronic assembly with a substrate having a structured metallization of at least 300 µm thickness, featuring first structures with heat-generating components and second structures without, and an electrical insulator with high thermal conductivity (>50 W/MK) to thermally connect adjacent structures, ensuring uniform heat distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional copper metallization is used for current conduction, then electrical conductivity is achieved, but thermal management efficiency deteriorates due to inability to distribute heat evenly

Engineering Contradiction:
Improvetemperature distribution uniformityVSAvoidcooler design complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent changes the physical parameter of metallization thickness from conventional thin layers to thick layers (≥300 μm, preferably ≥1 mm). This parameter change enables the metallization to function as both electrical conductor and heat spreader, resolving the contradiction by improving temperature distribution uniformity while avoiding complex cooler designs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The thick metallization layer performs multiple functions simultaneously: it conducts electrical current and distributes waste heat laterally. This multi-functionality eliminates the need for separate thermal management components, improving temperature uniformity without increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If thick metallization layers are used for heat distribution, then thermal management efficiency improves, but thermo-mechanical resistance deteriorates

Engineering Contradiction:
Improveheat distribution efficiencyVSAvoidthermo-mechanical resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent employs a composite substrate structure combining metal (for thermal conduction) with ceramic or plastic materials (for mechanical strength and CTE matching). This composite approach enables thick metallization layers to be implemented while maintaining thermo-mechanical reliability, as the ceramic or plastic substrate provides structural support and compensates for thermal expansion differences.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different material properties to different regions: thick copper metallization in areas requiring heat distribution, and ceramic or plastic substrate materials in areas requiring mechanical strength and thermal expansion compensation. This local differentiation resolves the contradiction between heat distribution efficiency and thermo-mechanical resistance.

Inventive Principle:
Principle #3Local quality

3Temperature

If ceramic substrates are used with thick metallization, then heat conduction improves, but mechanical reliability deteriorates due to CTE mismatch

Engineering Contradiction:
Improvethermal conductionVSAvoidthermo-mechanical stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent explicitly addresses thermal expansion by selecting substrate materials (ceramic or plastic) whose coefficient of thermal expansion (CTE) matches that of the thick copper metallization layer. This CTE matching prevents thermo-mechanical stress and delamination during thermal cycling, maintaining both thermal conduction and mechanical reliability.

Inventive Principle:
Principle #37Thermal expansion

Solution Approach 2:

The composite substrate structure combines materials with complementary properties: metal for thermal conduction, and ceramic or plastic for CTE matching and mechanical strength. This composite approach resolves the contradiction between heat conduction and thermo-mechanical stability.

Inventive Principle:
Principle #40Composite materials

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 solution achieves a more uniform heat distribution across the power electronic assembly, enhancing thermal management efficiency and allowing for higher performance or smaller semiconductor switches with the same performance.

Implementation Method 1

an electrical insulator is arranged at least in sections with respect to the gaps such that the structures adjacent to the gap are thermally connected by the insulator. The insulator has a thermal conductivity of at least 50 W/mK

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4341995B1Power electronics assembly
Publication Date: 2025.04.23 SIEMENS AG
  • EP4341995B1 patent drawingFigure 1
  • EP4341995B1 patent drawingFigure 2~3
  • EP4341995B1 patent drawingFigure 4~5

AI summary

The invention relates to a power electronics assembly (100) and to a method for manufacturing a semifinished product for a power electronics assembly (100). In order to specify an improved power electronics assembly (100), it is proposed that the assembly (100) has a substrate (20) with a metallization (30), which uses interspaces (40) to form first and second structures (35, 36) separated from one another, and has a thickness (D30) of at least 300 µm, a power semiconductor (50) being mounted on the first structures (35). At least portions of an electrical insulator (42) having a thermal conductivity of at least 50 W/mK are arranged relative to the interspaces (40) in such a way that the structures (35, 36) adjoining the respective interspaces (40) are thermally connected by the insulator (42).