Printed Wiring Board Resin Surface Via Adhesion
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Solution Overview
Problem
Existing printed wiring boards with insulating layers for build-up suffer from uneven relative permittivity due to exposed insulating particles, leading to variations in signal propagation speed and increased noise, especially when multiple signal wirings are involved.
Innovation Solution
A printed wiring board design featuring a resin insulating layer with inorganic particles, where the surface is smooth and only formed of resin, and a via conductor connecting conductor layers, with the inorganic particles exposed only on the inner wall of the via conductor opening, ensuring uniform relative permittivity and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If insulating particles are exposed on the surface of the insulating layer, then adhesion strength may be improved, but relative permittivity becomes uneven causing signal propagation speed variations and noise increase
Solution Approach 1:
The patent applies local quality by differentiating the composition between the surface region and the opening inner wall region of the insulating layer. The surface is formed only of resin material to ensure uniform relative permittivity and reduce noise, while the opening inner wall contains exposed insulating particles to maintain high adhesion strength. This spatial differentiation of material composition resolves the contradiction between adhesion strength and signal transmission quality.
2Ease of manufacture
If insulating particles are exposed on the surface, then manufacturing simplicity is maintained, but signal propagation speed varies due to uneven relative permittivity
Solution Approach 1:
The patent implements local quality by restricting insulating particle exposure to the opening inner wall while keeping the surface free of exposed particles. This localized approach maintains manufacturing simplicity through a single-layer structure with selective particle exposure, while ensuring uniform relative permittivity in the surface region for consistent signal propagation speed.
3Device complexity
If a single-layer insulating structure is used, then device complexity is reduced, but relative permittivity uniformity deteriorates due to exposed particles
Solution Approach 1:
The patent applies local quality within a single-layer insulating structure by creating distinct functional regions: a surface region composed only of resin for uniform relative permittivity, and an opening inner wall region with exposed insulating particles for adhesion. This localized material differentiation maintains structural simplicity while achieving composition stability and uniform relative permittivity in the signal transmission region.
Data Source
AI summary
A printed wiring board includes a first conductor layer, a resin insulating layer formed on the first conductor layer, a second conductor layer formed on a surface of the resin insulating layer and including a signal wiring, and a via conductor formed in the resin insulating layer such that the via conductor is connecting the first conductor layer and the second conductor layer. The resin insulating layer has an opening such that the opening is exposing a portion of the first conductor layer and that the via conductor is formed in the opening of the resin insulating layer, and the resin insulating layer includes inorganic particles and resin such that the resin is forming the surface of the resin insulating layer.