Printed Wiring Board Particle Embedding for Adhesion and Signal Uniformity

Solution Overview

Problem

Existing printed wiring boards face issues with conductor layer peeling due to thermal stress and non-uniform relative permittivity, leading to signal transmission speed differences and potential malfunctions.

Innovation Solution

A printed wiring board design featuring a resin insulating layer with first particles partially embedded and second particles completely embedded in the resin, where the first particles have exposed and covered surfaces, and the ratio of the second area (exposed surfaces) to the first area (total surface) is between 0.1 and 0.25, ensuring a stable conductor layer adhesion and uniform permittivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If particles are completely embedded in the resin insulating layer, then the surface is smooth and conductor layer adhesion is improved, but signal transmission speed uniformity deteriorates due to non-uniform relative permittivity distribution

Engineering Contradiction:

Improveconductor layer adhesionVSAvoidsignal transmission speed uniformity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies local quality by creating two distinct particle embedding configurations: completely embedded particles in certain regions to provide smooth surfaces for good conductor adhesion, and partially embedded particles in other regions to maintain uniform relative permittivity for consistent signal transmission. This spatial differentiation of particle embedding states allows each region to optimize for its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the particle population into two groups: first particles that are completely embedded in the resin and second particles that are partially embedded with exposed surfaces. This segmentation allows the insulating layer to simultaneously achieve smooth regions (from completely embedded particles) and uniform permittivity regions (from partially embedded particles), resolving the contradiction between adhesion and signal uniformity.

Inventive Principle:

Principle #1Segmentation

2Reliability

If particles are partially embedded in the resin insulating layer, then signal transmission speed uniformity is improved, but conductor layer adhesion deteriorates due to surface irregularities

Engineering Contradiction:

Improvesignal transmission speed uniformityVSAvoidconductor layer adhesion

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by creating two distinct particle embedding configurations: completely embedded particles in certain regions to provide smooth surfaces for good conductor adhesion, and partially embedded particles in other regions to maintain uniform relative permittivity for consistent signal transmission. This spatial differentiation of particle embedding states allows each region to optimize for its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the particle population into two groups: first particles that are completely embedded in the resin and second particles that are partially embedded with exposed surfaces. This segmentation allows the insulating layer to simultaneously achieve smooth regions (from completely embedded particles) and uniform permittivity regions (from partially embedded particles), resolving the contradiction between adhesion and signal uniformity.

Inventive Principle:

Principle #1Segmentation

3Reliability

If the ratio of exposed particle surface area to total surface area is increased, then signal transmission uniformity is improved, but the likelihood of conductor layer peeling increases

Engineering Contradiction:

Improvesignal transmission uniformityVSAvoidconductor layer adhesion

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies parameter changes by precisely controlling the ratio of exposed particle surface area to total surface area to fall within the range of 0.1 to 0.25. This quantitative parameter optimization ensures that there is enough exposed particle surface to maintain uniform relative permittivity for consistent signal transmission, while simultaneously limiting the exposed area to prevent excessive surface irregularities that would cause conductor layer peeling.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12279368B2Printed wiring board

Publication Date: 2025.04.15 IBIDEN CO LTD

AI summary

A printed wiring board includes a resin insulating layer including resin and particles, and a conductor layer formed on a surface of the resin insulating layer. The particles in the resin insulating layer include first particles and second particles such that the first particles are partially embedded in the resin and the second particles are completely embedded in the resin, and the resin insulating layer is formed such that the first particles has exposed surfaces exposed from the resin and covered surfaces covered by the resin, respectively, the surface of the resin insulating layer includes the first exposed surfaces, and a ratio of a second area to a first area is in a range of 0.1 to 0.25 where the first area is an area of the surface of the resin insulating layer, and the second area is obtained by summing areas of the exposed surfaces of the first particles.