Metal Coating Adhesion via Polymer Carboxylic Adsorption

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Solution Overview

Problem

Existing methods for applying metal coatings on substrates face challenges in achieving strong adhesion, uniformity, and resolution, particularly in large-scale production, and result in metal waste during the etching process for printed wire boards.

Innovation Solution

A method involving the production of polymers with carboxylic groups and adsorbed metal ions at a pH above 7, followed by reduction and deposition of the metal, which improves adhesion and allows for thinner metal layers, reducing waste and enabling more economical large-scale production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional electroless plating methods are used to apply metal coatings on substrates, then metal adhesion can be achieved, but the adhesion strength is insufficient and the process is not suitable for large-scale production

Engineering Contradiction:
Improvemetal adhesionVSAvoidlarge-scale production suitability
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The invention changes the pH parameter from acidic (traditional electroless plating) to basic (pH > 7), which fundamentally alters the chemistry of metal ion adsorption onto polymer carboxylic groups. This parameter change enables strong adhesion while maintaining process simplicity suitable for large-scale production

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces polymer carboxylic groups as an intermediary layer between the substrate and metal coating. These groups adsorb metal ions at basic pH, creating a strong chemical bridge that enhances adhesion. The polymer acts as a mediator that facilitates controlled metal deposition

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If thick metal layers are applied to ensure adequate coverage, then coverage is improved, but metal waste increases during the etching process

Engineering Contradiction:
Improvemetal layer coverageVSAvoidmetal waste
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The invention applies a thin layer of polymer carboxylic groups to the substrate surface before metal deposition. This preliminary action creates a controlled adsorption layer that ensures uniform metal distribution, allowing adequate coverage with thinner metal layers and reducing etching waste

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The polymer carboxylic groups are applied locally to the substrate surface where metal adhesion is needed. This localized treatment ensures metal is deposited only where required, improving coverage efficiency and reducing overall metal consumption and waste

Inventive Principle:
Principle #3Local quality

3Strength

If conventional metal deposition methods are used, then metal can be applied to the substrate, but adhesion strength and uniformity are insufficient

Engineering Contradiction:
Improveadhesion strengthVSAvoidcoating uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The polymer carboxylic groups serve as an intermediary layer that provides both mechanical anchoring and chemical bonding sites for metal ions. This intermediary ensures uniform metal distribution and strong adhesion, solving both the strength and uniformity problems simultaneously

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Changing to basic pH conditions alters the electrostatic interactions between polymer groups and metal ions, enabling uniform adsorption across the substrate surface. This parameter change ensures consistent metal distribution and uniform coating thickness

Inventive Principle:
Principle #35Parameter changes

4Shape

If etching processes are used to create patterns on metal-coated substrates, then desired patterns can be obtained, but significant metal waste occurs

Engineering Contradiction:
Improvepattern formationVSAvoidmetal waste
Core Design Contradiction:
ShapeVSLoss of substance

Solution Approach 1:

The polymer layer is applied preliminarily to define the future pattern areas. Metal is then deposited only on the polymer-coated regions, so when patterns are created, minimal metal needs to be removed. This preliminary patterning action drastically reduces metal waste during the etching process

Inventive Principle:
Principle #10Preliminary action

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 adhesion, reduces metal waste, and allows for the production of circuits with improved signal integrity and finer line widths, suitable for high-frequency applications and sequential layer manufacturing.

Implementation Method 1

producing polymers on the surface of said substrate, said polymers comprising carboxylic groups and adsorbed ions of at least one second metal

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

reducing said ions to the second metal and depositing said first metal on the reduced ions of said second metal

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP2004908B1Method for applying a metal on a substrate
Publication Date: 2009.06.17 LINEA TERGI

AI summary

There is disclosed a method for applying a first metal on a substrate, which method comprises the steps a) producing polymers on the surface of said substrate, said polymers comprising carboxylic groups and adsorbed ions of at least one second metal, said ions being adsorbed at a pH above 7, b) reducing said ions to the second metal and c) depositing said first metal on the reduced ions of said second metal. The invention further comprises objects manufactured according to the method. Advantages of the present invention include improved adhesion of the metal coating, possibility to coat many difficult materials. The process is suitable for large-scale and continuous production and it will reduce the waste of metal. Circuits manufactured according to the invention display improved signal integrity. Also there is the possibility to manufacture circuits which are built up sequentially with several layers of conductors in distinct patterns. It is also possible to manufacture of circuits with a very small line width.