Solid Electrolytic Capacitor Conductive Bridge Polymerization

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Solution Overview

Problem

The manufacturing of solid electrolytic capacitors with intrinsically conducting polymeric cathodes faces challenges such as high manufacturing costs, repetitive dip/dry cycles, variation in polymer coverage, and physical damage to the dielectric due to external electrical connections, which are complex and prone to damaging the active surface.

Innovation Solution

A method involving the formation of a conductive bridge between a conductive seed layer and an external electrical contact, allowing electrochemical polymerization of a monomer to create an electrically conducting polymer, followed by electroplating a metal layer, while disrupting the bridge to separate electrical contacts, thereby avoiding direct physical contact and minimizing damage to the dielectric.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external electrical contact is directly connected to conductive seed layer, then electrical connection is achieved, but physical damage to dielectric and polymeric cathode layer occurs

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidphysical damage to dielectric

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A conductive bridge layer is introduced as an intermediary between the external electrical contact and the conductive seed layer. This bridge layer serves as a mediator that enables electrical connection while preventing direct physical contact between the external hardware and the delicate dielectric/polymeric cathode layers, thus eliminating mechanical damage during assembly and handling.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrical connection path is segmented into multiple distinct layers: external electrical contact → conductive bridge layer → conductive seed layer → polymeric cathode layer. This segmentation allows each layer to perform its specific function independently, with the conductive bridge layer specifically tasked with providing mechanical support and electrical conductivity while protecting the underlying sensitive layers.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If repetitive dip/dry cycles are used for chemical in-situ polymerization, then sufficient polymer coverage is achieved, but manufacturing cost and process time increase

Engineering Contradiction:

Improvepolymer coverage uniformityVSAvoidmanufacturing efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

A conductive seed layer is formed on the dielectric surface before the polymerization process. This preliminary action creates a conductive foundation that enables effective electrochemical polymerization in a single dip cycle, eliminating the need for repetitive dip/dry cycles and significantly reducing manufacturing time while ensuring uniform polymer coverage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The mechanical repetitive dip/dry cycling process is replaced with an electrochemical polymerization process that occurs in situ on the conductive seed layer. This substitution uses electrical energy to drive the polymerization reaction, achieving sufficient and uniform polymer coverage in a single step rather than requiring multiple mechanical cycling operations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If complex hardware with external electrical contact is used, then electrical connection is achieved, but device complexity and potential for damage increase

Engineering Contradiction:

Improveelectrical connectionVSAvoidhardware complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The conductive bridge layer merges multiple functions into a single integrated layer: it provides electrical conductivity, mechanical support, and protection for the underlying dielectric and polymeric cathode layers. This consolidation eliminates the need for complex external hardware and multiple separate components, simplifying the overall device structure while maintaining reliable electrical connection.

Inventive Principle:

Principle #5Merging (Combining)

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 method enhances the efficiency of capacitor formation by reducing manufacturing costs and ensuring consistent polymer coverage without damaging the dielectric or anode layers, leading to improved capacitor performance and reliability.

Implementation Method 1

electrochemically polymerizing a monomer thereby forming an electrically conducting polymer of monomer on the conductive seed layer

Methodology Applied

Scientific EffectElectrochemical polymerization:

Implementation Method 2

electroplating a metal layer in electrical contact with said electrically conducting polymer

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS9583273B2Solid electrolytic capacitor and method of manufacturing a solid electrolytic capacitor

Publication Date: 2017.02.28 KEMET ELECTRONICS CORP

AI summary

Provided is a method for forming a capacitor. The method includes:providing an anode with a dielectric thereon and a conductive node in electrical contact with the anode;applying a conductive seed layer on the dielectric;forming a conductive bridge between the conductive seed layer and the conductive node;applying voltage to the anode;electrochemically polymerizing a monomer thereby forming an electrically conducting polymer of monomer on the conductive seed layer;plating a metal layer on said conductive polymer; anddisrupting the conductive bridge between the conductive seed layer and the conductive node.