Flexible Sacrificial Layer for Stretchable Conductor Anchoring

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Solution Overview

Problem

The challenge lies in producing metallic conductors with low resistivity on stretchable and flexible substrates while ensuring good adhesion, as existing methods face issues with conductors detaching during bending or stretching due to inadequate anchoring.

Innovation Solution

A method involving a flexible sacrificial layer with patterned conducting layers is bent into a desired shape before being embedded in a stretchable material, with an optional extra etch step to create gaps for better anchoring, ensuring the conductors remain securely embedded after the sacrificial layer is removed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conductors are deposited on rigid sacrificial substrates, then manufacturing process is simple, but conductors cannot be bent into desired shapes and adhesion fails during stretching

Engineering Contradiction:

Improvepredefined shape of conductorsVSAvoidmanufacturing process complexity

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

The sacrificial substrate is made flexible instead of rigid, allowing it to be dynamically bent into predefined shapes before conductor deposition. This flexibility enables the conductors to maintain the desired curved or bent shapes while preserving adhesion during subsequent stretching operations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The sacrificial substrate is pre-bent into the desired shape before the conducting layers are deposited. This preliminary shaping action ensures that the conductors are formed in the correct geometry from the start, eliminating the need for post-deposition shaping and reducing manufacturing complexity.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If conductors are embedded in stretchable material, then flexibility is achieved, but adhesion fails during bending or stretching

Engineering Contradiction:

Improvestretchability of substrateVSAvoidadhesion of conductor to substrate

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A flexible sacrificial substrate acts as an intermediary carrier that temporarily holds the conducting layers in the desired shape. This intermediary structure allows the conductors to be formed on a flexible base that can be stretched without failing adhesion, while the sacrificial nature of the substrate enables controlled removal after embedding.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical properties of the sacrificial substrate are optimized to be flexible yet maintainable, allowing it to withstand stretching during the embedding process. The substrate's parameters (flexibility, strength) are carefully selected to enable both stretchability and reliable adhesion during the manufacturing process.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS7487587B2Methods of producing a composite substrate

Publication Date: 2009.02.10 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)

AI summary

Methods of producing a composite substrate and devices made by the methods are disclosed. One of the methods comprises providing a flexible sacrificial layer, producing one or more patterned conducting layers on the flexible sacrificial layer, bending the sacrificial layer into a predetermined shape, providing a stretchable and/or flexible material on top of and in between features of the one or more patterned layers.