Fine Wiring Substrate With Sidewall Mesh for Adhesion Precision
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Solution Overview
Problem
Existing methods for manufacturing printed wiring substrates struggle to achieve precise formation of fine wirings with desired thickness and adhesion between conductor and insulating layers, particularly when using chemical etching which may compromise wiring thickness.
Innovation Solution
A method involving direct imaging exposure to form mesh-like unevenness on the side surfaces of conductor layers, replicating this pattern in the plating film layer, ensuring good adhesion with the insulating layer while maintaining flatness on the upper surface for precise wiring formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If chemical etching is used to form fine wirings, then wiring width and inter-wiring distance can be reduced, but wiring thickness precision and adhesion between conductor and insulating layers deteriorate
Solution Approach 1:
The patent replaces chemical etching with a physical deposition process (sputtering or evaporation) to form the conductor layer. This substitution allows precise control of wiring thickness through deposition parameters rather than chemical reactions, achieving both fine wiring dimensions and thickness precision simultaneously.
Solution Approach 2:
The patent changes the formation method parameter from chemical etching to physical deposition. By controlling deposition parameters such as deposition rate, substrate temperature, and atmosphere composition, the patent achieves precise control over both wiring width and thickness, eliminating the trade-off present in chemical etching methods.
2Strength
If mesh-like unevenness is formed on the upper surface of the conductor layer, then adhesion with insulating layer is improved, but wiring thickness precision and flatness for subsequent processing deteriorate
Solution Approach 1:
The patent applies local quality by forming mesh-like unevenness only on the side surfaces of the conductor layer while maintaining a flat upper surface. This localized modification provides adhesion enhancement where needed (at the interface with insulating layer) without compromising the flatness and thickness precision of the upper surface required for subsequent wiring formation.
Solution Approach 2:
The patent transitions from a two-dimensional flat conductor surface to a three-dimensional structure with controlled side surface unevenness. By confining the mesh-like pattern to the side surfaces rather than the upper surface, the patent adds vertical dimensionality for adhesion while preserving horizontal flatness for precision wiring formation.
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
Enables the formation of fine wirings with desired dimensions and enhances adhesion between conductor and insulating layers, maintaining flatness and fidelity to design specifications.
Implementation Method 1
exposing the resist layer by direct imaging exposure such that the openings have mesh-like unevenness formed on side walls of the resist layer
Implementation Method 2
forming a plating film layer on the metal film layer in the openings formed in the resist layer
Data Source
AI summary
A wiring substrate includes a first insulating layer, a conductor layer formed on the first insulating layer, and a second insulating layer formed on the first insulating layer such that the second insulating layer is covering the conductor layer. The conductor layer includes wirings formed such that the wirings have the minimum wiring width of 3 μm or less and the minimum inter-wiring distance of 3 μm or less and that the conductor layer has mesh-like unevenness formed on a side surface of the conductor layer and not on an upper surface of the conductor layer.