Housing-less Power Module with Direct Solder Contacts

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Solution Overview

Problem

Existing power modules face challenges with reliability due to breakage from vibrations and thermomechanical loads, and inefficient heat dissipation, especially as components become smaller, leading to complex thermal management or performance limitations.

Innovation Solution

A power module design featuring a heat sink with power components embedded in an insulating layer and a control unit arranged on top, allowing for efficient heat dissipation and electrical/thermal contact without a housing, using flip-chip technology and pressure contact for secure component placement, and integrating a printed circuit board for compactness and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bonding connections are used to connect power components to substrate, then electrical connection is achieved, but the bonding connections easily break under vibrations and thermomechanical loads

Engineering Contradiction:
Improveconnection reliabilityVSAvoidbonding connection strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent removes the bonding wire connections entirely and replaces them with direct solder connections between power components and the substrate. This extraction of the fragile bonding wire element eliminates its susceptibility to vibration-induced breakage while maintaining electrical connectivity through more robust solder joints.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical bonding wire system with a solder-based metallurgical bonding system. The solder connections provide both mechanical strength and electrical conductivity, eliminating the need for separate bonding wires that are vulnerable to mechanical stress and vibration.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional power module structure with housing is used, then component protection is achieved, but the module has very high inductance

Engineering Contradiction:
Improvemodule protectionVSAvoidinductance
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the traditional housing structure from the power module design. By eliminating the housing and采用 a housing-less construction, the patent reduces the loop area and parasitic inductance while still providing necessary component mounting and electrical connectivity through the substrate and terminal structure.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of moving object

If power components are made smaller to improve integration, then compactness is achieved, but heat dissipation becomes more difficult

Engineering Contradiction:
Improvemodule sizeVSAvoidheat dissipation
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The patent transitions from planar heat dissipation to three-dimensional heat management by implementing through-substrate vias and vertical heat pathways. Heat can now escape in multiple dimensions (through the substrate thickness and along vertical thermal paths) rather than being constrained to a single plane, enabling effective cooling of compact power components.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs composite substrate structures with materials optimized for both electrical performance and thermal conduction. The substrate integrates conductive pathways and thermal management layers that simultaneously support compact component placement and efficient heat removal, addressing both miniaturization and thermal dissipation requirements.

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 provides a compact, reliable, and efficient power module with enhanced heat dissipation and reduced inductance, enabling cost-effective manufacturing and improved performance without the need for a separate housing, while ensuring secure electrical and thermal connections.

Implementation Method 1

at least one power component arranged on the heat sink and thermally coupled to the heat sink for dissipating the waste heat produced by the at least one power component during operation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

an insulating layer covering the heat sink and the at least one power component

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP3271943B1Power module and method for producing a power module
Publication Date: 2020.01.15 SIEMENS AG
  • EP3271943B1 patent drawingFigure 1
  • EP3271943B1 patent drawingFigure 2

AI summary

The invention relates to a power module (1) comprising a power unit (2) and a drive unit (3) for driving the power unit (2). The power unit (2) has a heat sink (4), at least one power component (7) which is arranged on the heat sink (4), and an insulating layer (12) which covers the heat sink (4) and the at least one power component (7). In this case, a bottom face (17) of the power unit (2) is formed by a bottom face of the heat sink (4) and a top face (14) of the power unit (2) is formed by at least one contact area (16) which is thermally and/or electrically coupled to the at least one power component (7) and also a surface (15) of the insulating layer (12), which surface surrounds the at least one contact area (16). The drive unit (3) has at least one contact element (18) which corresponds to the at least one contact area (18) of the power unit (2) and which is arranged so as to bear against the at least one contact area (16) of the power unit (2) for making electrical and/or thermal contact with the at least one power component (7) on account of the drive unit (3) being arranged on the top face (14) of the power unit (2). The invention also relates to a method for producing a power module (1).