Printed Wiring Board Intermediate Compound Layer Adhesion
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Solution Overview
Problem
In printed wiring board manufacturing, the semi-additive method faces challenges in achieving fine-pitch conductive layers due to low adhesiveness between the plating resist and electroless copper-plated film, leading to peeling issues when forming narrow space width wiring layers.
Innovation Solution
The method involves forming an intermediate compound layer of Cu3N+Cu(NH)x on the electroless copper-plated film using microwave-excited plasma treatment, followed by electrolytic copper plating, which enhances adhesiveness to the plating resist and allows for the creation of fine-pitch conductive layers with electroless and electrolytic copper films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plating resist is formed directly on electroless copper-plated film, then the manufacturing process is simple, but adhesiveness is poor causing peeling
Solution Approach 1:
An intermediate compound layer of Cu3N+Cu(NH)x is introduced between the electroless copper-plated film and the plating resist. This intermediate layer serves as a mediator that enhances adhesiveness, preventing peeling while maintaining manufacturing simplicity. The intermediate layer is formed through microwave plasma treatment of the electroless copper-plated film before plating resist application.
2Productivity
If semi-additive method is used to form conductive layers, then manufacturing efficiency is improved, but fine-pitch conductive layers cannot be formed due to peeling
Solution Approach 1:
The intermediate compound layer Cu3N+Cu(NH)x acts as a mediator that enables fine-pitch conductive layer formation while maintaining the efficiency of the semi-additive method. By improving adhesiveness through this intermediate layer, the semi-additive method can successfully produce fine-pitch conductive layers without the peeling issues that previously limited its application to coarse pitches only.
3Ease of manufacture
If plating resist is removed after electrolytic plating, then the conductive layer structure is completed, but peeling occurs during the removal process
Solution Approach 1:
The intermediate compound layer Cu3N+Cu(NH)x serves as a protective mediator during the plating resist removal process. It maintains strong adhesion between the plating resist and the electroless copper-plated film, preventing peeling even when the plating resist is removed after electrolytic plating. This ensures the integrity of the conductive layer structure throughout the manufacturing process.
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 results in stable, fine-pitch conductive layers with improved adhesiveness, enabling the formation of narrow space width wiring patterns without peeling, enhancing the integration density of printed wiring boards.
Implementation Method 1
applying microwave plasma treatment on the electroless copper-plated film formed on the surface of the resin insulation layer and in the via opening such that an intermediate compound layer having Cu3N+Cu(NH)x is formed on the electroless copper-plated film
Implementation Method 2
applying electroless plating on the resin insulation layer such that an electroless copper-plated film is formed on a surface of the resin insulation layer and in the via opening
Implementation Method 3
applying electrolytic plating on a portion of the intermediate compound layer exposed from the plating resist layer such that an electrolytic copper-plated film is on the portion of the intermediate compound layer exposed from the plating resist layer
Data Source
AI summary
A printed wiring board includes resin insulation layers, conductive layers formed on the resin insulation layers respectively such that each of the conductive layers is formed on a surface of each of the resin insulation layers, and via conductors penetrating through the resin insulation layers respectively such that the via conductors are connecting the conductive layers through the resin insulation layers. The conductive layers and the via conductors are formed such that each of the conductive layers and each of the via conductors includes an electroless copper-plated film, an intermediate compound layer having Cu3N+Cu(NH)x and formed on the electroless copper-plated film, and an electrolytic copper-plated film formed on the intermediate compound layer.