Leadframe-Less Power Module Connectors for Low-Inductance Packaging

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing power modules for electric and hybrid propulsion vehicles face challenges due to the complexity of leadframe-based designs, which result in increased dimensions, parasitic inductances, and difficulties in modifying external pins and connections, limiting efficient use of space and adaptability.

Innovation Solution

A power module design that utilizes pillars attached to the substrate for signal and power connections, with variable connection ends and anti-extraction structures, embedded within an insulating housing to compensate for manufacturing inaccuracies and allow for flexible connection types such as press-fit, soldering, or screwing, reducing parasitic inductances and module dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If leadframe-based design is used for power modules, then electrical connections can be established, but the module dimensions increase and parasitic inductances are generated

Engineering Contradiction:
Improveelectrical connectionVSAvoidmodule dimensions
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent extracts and eliminates the leadframe structure from the power module design. Instead of using a traditional leadframe-based architecture, the invention directly mounts power semiconductor components on a substrate with integrated connection terminals, removing the intermediate leadframe layer that contributes to module size and parasitic inductance while maintaining electrical connection functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions from a planar leadframe-based connection architecture to a three-dimensional terminal structure that extends vertically from the substrate. The connection terminals protrude from the substrate surface, enabling electrical connections in a different spatial dimension and reducing the horizontal footprint and overall module dimensions

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

2Reliability

If leadframe-based design is used for power modules, then electrical connections can be established, but parasitic inductances are generated

Engineering Contradiction:
Improveelectrical connectionVSAvoidparasitic inductances
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the leadframe structure that generates parasitic inductances. By directly integrating connection terminals into the substrate and mounting components directly onto these terminals, the design eliminates the extended current paths and loop areas inherent in leadframe architectures, thereby reducing parasitic inductance

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the electrical connection path into minimal necessary components. Instead of a continuous leadframe structure, the design uses discrete, localized connection terminals on the substrate, creating shorter and more direct current paths that reduce parasitic inductance while maintaining connection reliability

Inventive Principle:
Principle #1Segmentation

3Reliability

If leadframe-based design is used for power modules, then power connections can be made, but the layout complexity increases due to safety isolation distances

Engineering Contradiction:
Improvepower connectionVSAvoidlayout complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses vertical terminal structures that extend from the substrate surface to establish power connections. This three-dimensional approach allows clearance and creepage distances to be maintained in the vertical dimension rather than consuming horizontal layout space, simplifying the overall module layout while maintaining safety isolation requirements

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

Solution Approach 2:

The substrate integrates multiple functions: it serves as the mechanical support, the electrical connection pathway, and the structure that provides safety isolation distances. The connection terminals simultaneously provide electrical connection and define the isolation geometry, reducing layout complexity compared to separate leadframe and substrate architectures

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

4Reliability

If leadframe-based design is used for power modules, then connections can be established, but the overall dimensions cannot be reduced

Engineering Contradiction:
ImproveconnectionVSAvoidmodule dimensions
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent removes the leadframe structure that dictates minimum module dimensions. Without the leadframe's mechanical constraints and extended geometry, the module can be compacted to smaller dimensions while maintaining connection reliability through the integrated substrate terminal architecture

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent relocates connection points to vertical terminals extending from the substrate surface, utilizing the vertical dimension for connections rather than requiring extended horizontal dimensions. This enables smaller footprint and overall module dimensions while maintaining reliable electrical connections

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

5Strength

If leadframe-based design is used for power modules, then structural support is provided, but the adaptability for modifying external pins and connections is reduced

Engineering Contradiction:
Improvestructural supportVSAvoidconnection modification
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The substrate with integrated connection terminals serves as a universal platform that can accommodate various connection types (soldering, press-fit, screw terminals) and external pin configurations. The terminal structures are designed to be adaptable to different connection methodologies while maintaining structural support, enabling greater design flexibility and modification capability compared to fixed leadframe architectures

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

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 simplifies connections, reduces module size, and maintains critical safety distances, enabling efficient use of space while allowing for adaptable and cost-effective assembly methods, comparable to existing solutions.

Implementation Method 1

The pillar is embedded in the housing 2 so that its lateral sides are completely or almost completely surrounded by and in contact with a packaging mass 3 that blocks the pillar

Methodology Applied
Scientific EffectMechanical support and electrical insulation:

Implementation Method 2

an electrical connector (5), coupled to the electronic component (15A, 15B) or to a second connection region (14C) of the plurality of connection regions, the electrical connector (5) extending towards the main surface (2A) of the housing (2; 102), transversely thereto

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4258832A1Power module having leadframe-less signal connectors, in particular for automotive applications, and assembling method thereof
Publication Date: 2023.10.11 STMICROELECTRONICS SRL
  • EP4258832A1 patent drawingFigure 1~3
  • EP4258832A1 patent drawingFigure 4~6C
  • EP4258832A1 patent drawingFigure 7A~8

AI summary

Power module (1) packaged in a housing (2) accommodating a carrying substrate (10) forming a plurality of connection regions (14A-14D) of conductive material. An electronic component (15A, 10B) is arranged inside the housing, attached to a connection region (14A, 14B) of the plurality of connection regions (14A-14D). An electrical connector (5), coupled to the electronic component, extends towards the main surface (2A) of the housing (2) and is accessible from the outside of the housing. The electrical connector has a tubular portion forming a pillar (8) fixed to a pin which protrudes from the main surface of the housing. The housing (2) includes a packaging mass (3) of electrically insulating material that embeds the pillar (8) and blocks it therein.