Multilayer Electrical Node Embedding for Thermal Stress Management

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Solution Overview

Problem

Existing electronic assembly methods face challenges in integrating dense and complex components into multilayer structures due to reliability risks, assembly yield issues, and thermal management problems, particularly with mismatched thermal expansion coefficients and complex geometries, leading to potential overheating and structural stress.

Innovation Solution

A multilayer structure and manufacturing method involving a substrate film with cavities filled by a material layer to embed electrical elements, incorporating thermal management elements and elastic materials for improved integration and reduced complexity, with a molded or cast material layer covering the electrical nodes to enhance reliability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If complex electrical circuits are produced on a substrate by printing and/or utilizing SMDs and then overmolded by plastic material, then the desired functionality is achieved, but reliability risks and assembly yield issues arise due to challenges in integrating dense components and components with complex geometries

Engineering Contradiction:
ImprovefunctionalityVSAvoidassembly yield
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent divides the substrate into multiple layers with electrical circuits distributed across different levels. This segmentation allows complex functionalities to be achieved while reducing the density of components on any single layer, thereby improving assembly yield and reliability during the overmolding process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from two-dimensional circuit layouts to three-dimensional multilayer structures. By stacking multiple substrate layers and routing circuits through vertical vias, the design achieves complex functionality without increasing planar component density, thus avoiding the reliability issues associated with dense single-layer configurations.

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

2Adaptability or versatility

If dense components and components of complex geometry are directly integrated, then the degree of integration is improved, but reliability is affected by molding pressure and assembly yields in different production phases become very low

Engineering Contradiction:
Improvedegree of integrationVSAvoidassembly yield
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the integrated circuit system into multiple substrate layers, each containing a subset of the total components. This segmentation maintains high overall integration while reducing the local component density and geometric complexity on each layer, making the assembly process more reliable and less susceptible to molding pressure defects.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a nested structure where multiple substrate layers are stacked and interconnected through vias. This nested arrangement achieves high integration by embedding multiple circuit levels within a compact volume, while each individual layer remains simple enough to maintain high assembly yields during manufacturing.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Strength

If subassemblies are mounted or arranged on a PCB and covered with a plastic layer, then the structure is protected, but mismatch in thermal expansion coefficients causes stresses that can tear the subassemblies off their electrical contacts

Engineering Contradiction:
ImproveprotectionVSAvoidelectrical contact integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the material parameters of the substrate and encapsulant to achieve better thermal expansion matching. By selecting materials with compatible coefficients of thermal expansion, the design reduces thermally-induced stresses that would otherwise tear electrical contacts from subassemblies during temperature cycling.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures combining the PCB substrate, mounting subassemblies, and encapsulant plastic. This composite approach allows optimization of thermal expansion properties across the entire assembly, reducing differential stress and maintaining electrical contact integrity under thermal loading.

Inventive Principle:
Principle #40Composite materials

4Adaptability or versatility

If complex electrical circuits are produced to achieve desired functionalities, then the functionality is improved, but the complexity of the structure increases making it difficult to be overmolded

Engineering Contradiction:
ImprovefunctionalityVSAvoidovermolding difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent segments the circuit implementation across multiple substrate layers, which simplifies the geometry of each individual layer and makes the overall structure more amenable to overmolding. The segmented approach maintains full functionality while reducing manufacturing complexity compared to attempting to integrate all circuits on a single complex layer.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3845039B1Multilayer structure comprising an electrical node and method for manufacturing the same
Publication Date: 2024.06.12 TACTOTEK
  • EP3845039B1 patent drawingFigure 1~3
  • EP3845039B1 patent drawingFigure 4A~4D
  • EP3845039B1 patent drawingFigure 5A~5B

AI summary

An electrical node (100), a method, an electrical assembly such as a node strip or sheet, a related multilayer structure and a method of manufacture are presented. The electrical node comprises a first substrate film (10) defining a cavity, and a first material layer (30) arranged to at l east partly fill the cavity, and to embed or at l east partly cover at l east one electrical element (12) arranged into the cavity.