Power Semiconductor Module Thermal Interface with Conductive Whiskers

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Solution Overview

Problem

Current power semiconductor module arrangements face challenges in achieving adequate thermal conductivity between the substrate or base plate and the heat sink, as existing heat-conducting pastes often have thermal conductivities below the required levels for efficient heat dissipation.

Innovation Solution

Incorporating a heat-conducting paste with evenly distributed thermally conducting particles and whiskers or fibers, where the fibers have one end connected to either the substrate or heat sink, enhancing thermal conductivity by creating additional thermal paths and bridging sections of low conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional heat-conducting paste is used between substrate and heat sink, then the arrangement is simple to manufacture, but thermal conductivity is insufficient (below required levels)

Engineering Contradiction:
Improvethermal conductivityVSAvoidheat-conducting paste composition
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The heat-conducting paste is formulated as a composite material containing thermally conductive particles (such as metal particles, ceramic particles, or carbon-based materials) dispersed in a paste matrix. This composite structure enables the paste to achieve high thermal conductivity (exceeding 200W/mK) while maintaining its function as an interface material between the substrate and heat sink.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The thermal conductivity parameter of the heat-conducting paste is significantly enhanced by incorporating thermally conductive particles with high thermal conductivity values. The particle concentration, size distribution, and material composition are optimized to achieve thermal conductivity exceeding 200W/mK, transforming the paste from a low-conductivity material to a high-performance thermal interface material.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If thermally conductive particles are added to heat-conducting paste, then thermal conductivity increases, but manufacturing complexity increases

Engineering Contradiction:
Improvethermal conductivityVSAvoidpaste production process
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The manufacturing process parameters are optimized to achieve uniform dispersion of thermally conductive particles in the paste matrix. Particle concentration, size distribution, and surface treatment parameters are carefully controlled to ensure high thermal conductivity while maintaining manufacturability through standard mixing and coating techniques.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The thermally conductive particles are strategically distributed within the heat-conducting paste to create optimal thermal pathways. The particle distribution and orientation are controlled to maximize thermal conductivity in the direction of heat flow while maintaining ease of application and manufacturing.

Inventive Principle:
Principle #3Local quality

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 configuration significantly increases thermal conductivity, improving heat dissipation between the substrate and heat sink, potentially exceeding thermal conductivities of up to 200W/mK, thereby addressing the limitations of conventional heat-conducting pastes.

Implementation Method 1

a plurality of thermally conducting particles is evenly distributed within the heat-conducting paste... significantly increases thermal conductivity, improving heat dissipation between the substrate and heat sink

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3624182B1Power semiconductor module arrangement, substrate arrangement, and method for producing the same
Publication Date: 2022.04.20 INFINEON TECHNOLOGIES AG
  • EP3624182B1 patent drawingFigure 1~3
  • EP3624182B1 patent drawingFigure 4~5
  • EP3624182B1 patent drawingFigure 6A~6B

AI summary

A power semiconductor module arrangement comprises a heat sink (30), a substrate arrangement (60) arranged on the heat sink (30) in a vertical direction, a heat-conducting paste (40) arranged between a surface (61) of the substrate arrangement (60) and a surface (31) of the heat sink (30) in the vertical direction, wherein a plurality of thermally conducting particles is evenly distributed within the heat-conducting paste (40), and a plurality of whiskers or fibers (64). Each of the plurality of whiskers or fibers (64) comprises a first end and a second end, and the first end of each of the plurality of whiskers or fibers (64) is inseparably connected to either the surface (61) of the substrate arrangement (60) or to the surface (31) of the heat sink (30).