Wiring Board Dual Conductive Layer Adhesion
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Solution Overview
Problem
The challenge in manufacturing coreless wiring boards is maintaining the width and thickness of wiring layers while preventing the resist layer from falling due to the reduction in size, as roughening treatment reduces the wiring layer width, making it difficult to achieve desired dimensions and adhesion.
Innovation Solution
A wiring board structure with a first conductive layer and a second conductive layer, where the second conductive layer coats the first conductive layer and its sides, providing roughened surfaces for increased adhesion without the need for roughening treatment on the first conductive layer, allowing for stable width and thickness retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If roughening treatment is applied to the wiring layer surface to increase adhesion, then adhesion between insulating layer and wiring layer is improved, but the wiring layer width becomes smaller
Solution Approach 1:
The wiring layer is segmented into two distinct conductive layers: a first conductive layer maintaining smooth surfaces for width preservation, and a second conductive layer with roughened surfaces for adhesion enhancement. This segmentation allows each layer to fulfill its specific function without compromising the other.
Solution Approach 2:
Different surface qualities are applied to different parts of the wiring structure. The first conductive layer maintains smooth surfaces where width precision is critical, while the second conductive layer has roughened surfaces specifically where adhesion is needed for the insulating layer.
2Manufacturing precision
If the wiring layer width is reduced to achieve desired dimensions, then manufacturing precision is improved, but the resist layer becomes more liable to fall-down
Solution Approach 1:
The wiring layer is divided into two conductive layers with different functions. The first conductive layer provides the precise width dimensions needed for manufacturing accuracy, while the second conductive layer provides the roughened surface for adhesion, eliminating the need to reduce the first layer's width and thus preventing resist layer fall-down.
Solution Approach 2:
The second conductive layer acts as an intermediary between the first conductive layer and the insulating layer. It provides the roughened surface for adhesion while the first conductive layer maintains the precise width, serving as a mediator that resolves the conflict between precision and stability.
3Length of moving object
If the width of the first conductive layer is formed widely to compensate for roughening treatment reduction, then the desired wiring width can be obtained, but the resist layer width must be made smaller increasing fall-down risk
Solution Approach 1:
The wiring structure is segmented into two conductive layers where the first layer defines the precise width dimensions and the second layer provides adhesion. This eliminates the need to form the first layer with excessive width compensation, allowing the resist layer to maintain adequate width without fall-down risk.
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 enhances adhesion between layers, prevents resist layer fall-down, and allows for easier size reduction of wiring layers without compromising structural integrity or transmission characteristics.
Implementation Method 1
a second conductive layer which coats a first surface and a side surface of the first conductive layer
Data Source
AI summary
A wiring board includes a first wiring layer including a first conductive layer and a second conductive layer coating a first surface and a side surface of the first conductive layer. A first insulating layer covers a first surface and a side surface of the second conductive layer so as to expose a second surface of the first conductive layer opposite to the first surface of the first conductive layer. A second wiring layer is stacked on a first surface of the first insulating layer and is electrically connected to the first wiring layer. The first surface and the side surface of the first conductive layer are smooth surfaces while the first surface and the side surface of the second conductive layer are roughened-surfaces.