Power Semiconductor Module Pressure Element Thermal Coupling

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Solution Overview

Problem

Conventional power semiconductor modules face challenges in achieving optimal heat transfer due to the low thermal conductivity of thermally conductive materials used between the baseplate and heat sink, while also requiring efficient fabrication and avoiding damage to bonding wires.

Innovation Solution

A power semiconductor module design that includes a support, a power semiconductor chip, a pressure element, and a bonding wire, where the pressure element exerts contact pressure on the top side of the chip towards the heat sink, reducing the thickness of the heat conducting element and enhancing thermal coupling, and a method for fabricating this module with a pressure element arranged distant from the bonding wire to prevent damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermally conductive material is introduced between the baseplate and heat sink to compensate for irregularities, then thermal coupling is improved, but the thermal conductivity decreases due to the material's lower thermal conductivity

Engineering Contradiction:

Improvethermal couplingVSAvoidthermal conductivity

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by transforming the rigid, fixed-position baseplate into a flexible system that can adapt its position and contact pressure. The pressure element enables dynamic adjustment of the baseplate's position relative to the heat sink, optimizing thermal contact while minimizing the impact of low-conductivity thermal material. This dynamic parameter adjustment resolves the contradiction by allowing optimal thermal coupling without being constrained by the thermal material's inherent low conductivity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the power semiconductor module is pressed against the heat sink to improve heat transfer, then thermal coupling is enhanced, but the bonding wires may deform or short-circuit

Engineering Contradiction:

Improvethermal couplingVSAvoidbonding wire damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies segmentation by separating the functions of thermal pressing and electrical connection. The pressure element is positioned distant from the bonding wires, creating distinct functional zones: one for applying pressing force to improve thermal coupling, and another for maintaining intact bonding wire connections. This spatial segmentation resolves the contradiction by allowing independent optimization of both thermal contact and electrical connection integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary element - the pressure element - that mediates between the need for pressing force and the vulnerability of bonding wires. This intermediary applies the necessary mechanical force to improve thermal coupling while being positioned such that it does not directly contact or damage the bonding wires, thus resolving the contradiction through functional mediation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If the baseplate is made rigid to maintain structural stability, then mechanical strength is improved, but the ability to adapt to heat sink irregularities decreases

Engineering Contradiction:

Improvestructural stabilityVSAvoidadaptation to heat sink irregularities

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by introducing a flexible baseplate that can adapt its position and shape in response to heat sink irregularities. The pressure element enables dynamic adjustment of the baseplate's contact pressure and position, allowing the system to maintain both structural stability and adaptability. The flexible baseplate can deform to conform to surface irregularities while the pressure element provides the necessary force to maintain optimal thermal contact.

Inventive Principle:

Principle #15Dynamics

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 design improves heat dissipation and thermal coupling between the power semiconductor chips and the heat sink, ensuring efficient cooling and preventing damage to the bonding wires during assembly.

Implementation Method 1

the pressure element, which is arranged distant from the bonding wire, exerts a contact pressure on the top in the direction of the heat sink

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

improves the transfer of heat, a thermally conductive material... may be introduced between the baseplate and the heat sink

Methodology Applied

Scientific EffectPressure-induced thermal coupling:

Data Source

PatentUS7808100B2Power semiconductor module with pressure element and method for fabricating a power semiconductor module with a pressure element

Publication Date: 2010.10.05 INFINEON TECHNOLOGIES AG

AI summary

The invention relates to a power semiconductor module comprising at least one power semiconductor chip, and comprising a pressure apparatus which exerts a pressure on the top side of the power semiconductor chip when the power semiconductor module is fixed to a heat sink. In addition, a bonding wire which is arranged distant from the pressure element, is bonded to the top side. The invention also relates to methods for fabricating a power semiconductor module, and for fabricating a power semiconductor arrangement comprising a power semiconductor module and a heat sink.