Seamless Insulation for Multi-Electrode Arrays
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Solution Overview
Problem
Standard polymer-based multi-electrode arrays (MEAs) face delamination issues due to water and bodily fluid infiltration at polymer-polymer and polymer-metal interfaces, leading to device failure, and existing adhesion improvement methods are either ineffective or detrimental to metal thin films.
Innovation Solution
A method of fabricating MEAs by suspending thin-film electrically conductive trace beams over a substrate, encapsulating them in a seamless block of insulating material, and exposing the conductive surfaces, reducing the number of interfaces prone to delamination through reproducible microfabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple layers of polymers are coated layer by layer to insulate conductive wiring, then insulation coverage is achieved, but delamination and separation occur at polymer-polymer and polymer-metal interfaces due to water and bodily fluid infiltration
Solution Approach 1:
The patent eliminates the multi-layer polymer structure and replaces it with a single seamless insulating layer formed by encapsulating the conductive traces in a suspenDED state. This segmentation principle is applied by removing the sacrificial substrate beneath the traces, allowing the insulating material to be deposited continuously without interfaces, thereby eliminating delamination pathways.
Solution Approach 2:
The patent introduces a sacrificial substrate as an intermediary element that enables the traces to be suspended during the insulating material deposition process. This intermediary allows the insulating material to conformally coat all surfaces of the traces uniformly, creating a seamless encapsulation that prevents fluid infiltration and delamination.
2Strength
If polymer treatment methods are applied to improve adhesion between polymer layers, then adhesion may be enhanced, but the treatment parameters are detrimental to metal thin films
Solution Approach 1:
The patent applies preliminary action by suspending the conductive traces from the substrate before depositing the insulating material. This preliminary suspension allows the insulating material to be deposited conformally on all surfaces of the traces without requiring subsequent polymer treatment steps that would compromise the metal thin films, thereby ensuring both adhesion and metal integrity.
3Strength
If the substrate is retained during encapsulation, then structural support is maintained, but the conductive surfaces cannot be exposed for electrical connection
Solution Approach 1:
The patent applies the taking out principle by selectively removing the sacrificial substrate beneath the suspended traces after the insulating material has been deposited. This extraction allows the conductive surfaces to be exposed through the insulating material for electrical connection while maintaining the structural integrity of the encapsulated traces during the encapsulation process.
Data Source
AI summary
Thin-film multi-electrode arrays (MEA) having one or more electrically conductive beams conformally encapsulated in a seamless block of electrically insulating material, and methods of fabricating such MEAs using reproducible, microfabrication processes. One or more electrically conductive traces are formed on scaffold material that is subsequently removed to suspend the traces over a substrate by support portions of the trace beam in contact with the substrate. By encapsulating the suspended traces, either individually or together, with a single continuous layer of an electrically insulating material, a seamless block of electrically insulating material is formed that conforms to the shape of the trace beam structure, including any trace backings which provide suspension support. Electrical contacts, electrodes, or leads of the traces are exposed from the encapsulated trace beam structure by removing the substrate.