Isolated Power Packaging With Exposed Contacts for Creepage Control

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Solution Overview

Problem

Existing semiconductor packaging technologies lack flexibility in creating various lead connections and suffer from voltage creepage due to the distance between leads, which is inadequate for power electronics substrates that require higher current carrying and voltage isolation.

Innovation Solution

The proposed solution involves an isolated substrate packaging system with a housing that encapsulates electronic components and includes openings for exposing metallized surfaces, allowing for direct coupling with lead terminals through methods like wire-bonding, electrically-conductive clips, or soldering, using materials like copper or epoxy, enabling flexible mounting options such as through-hole or surface mounting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional packaging technologies are used, then the structure is simple and easy to manufacture, but the flexibility in creating various lead connections is insufficient and voltage creepage occurs

Engineering Contradiction:
Improveflexibility in lead connectionsVSAvoidpackaging structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The packaging structure is segmented into distinct functional zones: encapsulation regions for protecting electronic components and exposed metallized surface regions for lead connections. The bottom side of the housing includes specific openings that expose metallized surfaces at designated locations, allowing flexible lead terminal arrangements without complicating the overall packaging structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes the third dimension by exposing metallized surfaces on the bottom side of the housing through strategically positioned openings. This vertical arrangement of connection points allows for flexible lead terminal configurations in multiple spatial dimensions, enabling various mounting options (through-hole, surface mount) without increasing planar complexity

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

2Reliability

If leads are positioned close together to reduce voltage creepage, then voltage isolation is improved, but the distance between leads becomes insufficient for proper electrical isolation

Engineering Contradiction:
Improvevoltage isolationVSAvoiddistance between leads
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

Different regions of the packaging structure have different electrical properties: areas with exposed metallized surfaces provide low-impedance electrical connections, while the housing material (epoxy or plastic) provides high electrical resistance for isolation. This local differentiation of electrical qualities allows leads to be positioned close together physically while maintaining adequate electrical isolation through the housing material

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If direct access to metallized surfaces is provided for lead connections, then connection flexibility is improved, but the electronic components become more exposed to environmental damage

Engineering Contradiction:
Improveconnection flexibilityVSAvoidenvironmental exposure
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The housing structure is segmented into encapsulated regions that protect electronic components from environmental factors and exposed regions that provide access to metallized surfaces for connections. This segmentation allows the beneficial exposure of connection surfaces while maintaining protection of sensitive components

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The housing structure acts as an intermediary that selectively exposes only the necessary metallized surfaces for lead connections while keeping the rest of the electronic components encapsulated and protected. The openings in the housing serve as controlled interfaces between the protected internal environment and the external connection environment

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach provides improved thermal management and flexibility in lead connections, reducing voltage creepage and enhancing the reliability and efficiency of power electronics packaging by allowing direct access to surface connections and accommodating various applications.

Implementation Method 1

Power electronic substrates carry higher currents and provide a higher voltage isolation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The power electronics substrate both provides the interconnections to form an electrical circuit and cool the components

Methodology Applied
Scientific EffectThermal convection: Convection

Implementation Method 3

The metallized surfaces may be configured for coupling to one or more lead terminals

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 4

One or more semiconductor chips and one or more electronic components may be configured to be coupled using at least one of the following: wire-bonding, one or more electrically-conductive clips, silver-sintering, soldering

Methodology Applied
Scientific EffectSoldering: Soldering

Data Source

PatentEP4354498A1Isolated power packaging with flexible connectivity
Publication Date: 2024.04.17 LITTELFUSE INC
  • EP4354498A1 patent drawingFigure 1A~1E
  • EP4354498A1 patent drawingFigure 1F
  • EP4354498A1 patent drawingFigure 2

AI summary

An isolated packaging structure and methods thereof. The structure includes a housing having a top side and a bottom side. The housing encapsulates one or more electronic components. The structure also include one or more openings disposed in the bottom side of the housing. One or more openings are configured for exposing one or more metallized surfaces of one or more electronic components. One or more metallized surfaces are configured for coupling to one or more lead terminals.