Electroless Copper Plating for Wiring Board Interface Continuity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The continuity between the seed layer and the electrolytic copper plating layer in wiring boards formed by electrolytic copper plating is often insufficient, leading to discontinuities and reduced reliability, especially when finer wirings are required.

Innovation Solution

A method involving a laminate with an insulating material layer and an electroless copper plating layer, where a resist pattern is formed and filled with a conductive copper material using electrolytic copper plating, ensuring excellent adhesiveness and continuity between the layers, and a copper layer with carrier is used for uniform thickness and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If electrolytic copper plating is performed directly on a seed layer, then fine wirings can be formed, but continuity between the seed layer and electrolytic copper plating layer is insufficient

Engineering Contradiction:

Improvefine wiring formationVSAvoidcontinuity between layers

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent segments the copper plating process into two distinct stages: first forming an electroless copper plating layer on the seed layer, then performing electrolytic copper plating on top of the electroless layer. This segmentation allows each process to optimize for its specific function - the electroless plating ensures continuous coverage and adhesion to the seed layer, while the electrolytic plating provides the desired fine wiring precision and conductive material properties.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electroless copper plating layer is formed as a preliminary action before the electrolytic copper plating. This preliminary layer serves as an intermediate foundation that ensures continuity and adhesion between the seed layer and the subsequent electrolytic copper plating, preventing discontinuities that would occur if electrolytic plating were performed directly on the seed layer.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If a copper foil formed with rolling is used, then manufacturing is simplified, but a discontinuous interface is interposed between the copper foil and electroless copper plating layer

Engineering Contradiction:

Improvecopper foil processingVSAvoidinterface continuity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the surface characteristics and deposition mechanism parameters by using electroless copper plating instead of directly using rolled copper foil. The electroless plating process creates a chemically bonded, continuous copper layer that eliminates the discontinuous interface problem inherent in mechanically rolled copper foils, while still maintaining ease of manufacture through standard plating processes.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If finer wirings are required, then high-density conduction is achieved, but reliability improvement is limited due to interface discontinuities

Engineering Contradiction:

Improvewiring finenessVSAvoidinterface adhesion

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent creates a composite copper structure consisting of multiple layers: seed layer, electroless copper plating layer, and electrolytic copper plating layer. Each layer contributes specific properties - the electroless layer provides continuous adhesion to the seed layer, while the electrolytic layer provides fine wiring precision. This composite structure achieves both fine wiring capability and high reliability at the interfaces.

Inventive Principle:

Principle #40Composite materials

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 approach enables the manufacture of wiring boards with fine, reliable conductive portions by ensuring high continuity at the interface between the electroless and electrolytic copper layers, facilitating further miniaturization and reducing labor and time in the manufacturing process while minimizing variations in cross-sectional areas.

Implementation Method 1

providing a laminate comprising an insulating material layer and a copper layer which is an electroless copper plating layer formed on a surface of the insulating material layer

Methodology Applied

Scientific EffectElectroless plating: Electroplating

Implementation Method 2

filling the groove with a conductive material containing copper by electrolytic copper plating

Methodology Applied

Scientific EffectElectrolytic plating: Electroplating

Data Source

PatentUS20240057263A1Method for producing wiring board, laminate and method for producing same

Publication Date: 2024.02.15 RESONAC CORP

AI summary

A method for manufacturing a wiring board including: providing a laminate including an insulating material layer and a copper layer provided on a surface of the insulating material layer, and in which the copper layer is an electroless copper plating layer; forming a resist pattern including a groove reaching a surface of the copper layer on the surface of the copper layer; and filling the groove with a conductive material containing copper by electrolytic copper plating. The thickness of the electroless copper plating layer is, for example, 20 nm to 200 nm.