Metal Wiring Development Process for Complete Coating Removal

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Solution Overview

Problem

Existing methods for forming metal wires using laser light irradiation result in residual coating outside the intended wire pattern, leading to issues like metal growth and short-circuiting, and physical development processes damage the wires.

Innovation Solution

A method involving a two-step development process using specific solvents and additives in the developers to effectively remove residual coating, including a first developer with organic solvents and additives like surfactants and dispersants, followed by a second developer with higher metal solubility, to prevent damage and ensure complete removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single development process is used to remove residual coating, then the process is simple and quick, but the coating cannot be sufficiently removed leading to metal growth and short-circuiting

Engineering Contradiction:
Improveremoval completeness of residual coatingVSAvoidcomplexity of development process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The development process is divided into two sequential stages: first development using a first developer to remove loosely adhered residual coating, and second development using a second developer to remove tightly adhered residual coating. This segmentation allows each developer to be optimized for its specific removal task, achieving complete coating removal while preventing metal wire damage that would occur with a single aggressive development step.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If physical force such as ultrasonic waves is applied during development to enhance coating removal, then the coating removal effect is improved, but the metal wire is damaged leading to breakage and increased resistance

Engineering Contradiction:
Improvecoating removal efficiencyVSAvoidintegrity of metal wire
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent replaces mechanical/physical force methods (ultrasonic waves) with chemical methods (selective developers). The first developer uses mild chemical action to remove loose coating without physical agitation, while the second developer uses stronger chemical action to remove tight coating. This substitution of mechanical action with chemical action achieves effective coating removal while preserving metal wire integrity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If conventional photoresist method is used to form wire pattern, then the pattern can be precisely formed, but the process has many steps and requires photoresist material

Engineering Contradiction:
Improvewire pattern precisionVSAvoidnumber of manufacturing steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the photoresist application, exposure, and development steps from the conventional multi-step process. Instead of using photoresist to define the pattern, the invention directly applies metal particles in the desired wire pattern configuration onto the substrate, followed by sintering. This extraction of the photoresist system reduces the number of manufacturing steps while maintaining pattern precision.

Inventive Principle:
Principle #2Taking out (Extraction)

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

The method ensures thorough removal of residual coating without damaging the metal wires, improving the integrity and conductivity of the final product.

Implementation Method 1

a first development process to develop and remove a region of the dried coating other than the metal wire by a first developer, and a second development process of developing and removing a region of the dried coating other than the metal wire by a second developer

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

the coating is then irradiated with laser light in a pattern and selectively fired to obtain a desired pattern

Methodology Applied
Scientific EffectPhotothermal heating: Heating

Data Source

PatentEP4210073B1Production method for metal wiring and kit
Publication Date: 2025.10.22 ASAHI KASEI KOGYO KABUSHIKI KAISHA
  • EP4210073B1 patent drawingFigure 1(a)~1(k)
  • EP4210073B1 patent drawingFigure 2~3
  • EP4210073B1 patent drawingFigure 4~5

AI summary

Provided are a production method for metal wiring and a kit that make it possible to fully remove a coating film from between metal wiring during a development step. The production method for metal wiring that is one aspect of the present invention has a development step that includes first development processing that develops and removes a dried coating film from regions not at metal wiring by means of a first development liquid. The first development liquid includes a solvent and an additive (A). The solvent is an organic solvent or water or a mixture thereof. The organic solvent is one or more types of solvent selected from the group that consists of alcohol solvents, ketone solvents, ester solvents, amine solvents, and ether solvents. The concentration of the additive (A) in the first development liquid is 0.01-20 mass%.