Variable-Thickness Wiring Layout for Narrow Trace Reliability

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Solution Overview

Problem

Existing wiring substrates face challenges in maintaining consistent electrical resistance and reducing the risk of disconnection, particularly in sections with narrower wiring widths.

Innovation Solution

The wiring substrate design includes sections with varying widths and thicknesses, where the second section with a smaller width has a larger thickness than the first section, ensuring consistent cross-sectional areas and reducing the risk of disconnection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the wiring width is reduced to achieve higher integration or routing flexibility, then the wiring density and routing capability are improved, but the electrical resistance increases and the risk of disconnection increases

Engineering Contradiction:

Improvewiring densityVSAvoidelectrical resistance consistency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by varying the wiring thickness at different sections of the same wiring. Specifically, the wiring has a first section with a first thickness and a second section with a second thickness that is greater than the first thickness. This allows different parts of the wiring to have different properties optimized for their specific functions: the thinner first section for routing flexibility and the thicker second section for lower resistance and higher reliability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of wiring thickness along the length of the wiring. By increasing the thickness in the second section compared to the first section, the patent modifies the electrical resistance parameter locally to maintain consistent electrical characteristics throughout the wiring, thereby resolving the contradiction between reduced wiring width and maintained electrical resistance consistency.

Inventive Principle:

Principle #35Parameter changes

2Area of stationary object

If the wiring width is reduced to achieve higher integration, then the substrate area utilization is improved, but the mechanical strength and connection reliability deteriorate

Engineering Contradiction:

Improvesubstrate area utilizationVSAvoidwiring mechanical strength

Core Design Contradiction:

Area of stationary objectVSStrength

Solution Approach 1:

The patent applies local quality by making the second section of the wiring thicker than the first section. This localized increase in thickness provides enhanced mechanical strength and reduced disconnection risk in the second section while maintaining the overall compact design and high substrate area utilization achieved through the reduced wiring width.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent resolves the area-strength contradiction by transitioning from a two-dimensional width adjustment to a three-dimensional solution that varies thickness (the third dimension). By controlling the wiring thickness in the vertical dimension rather than only the horizontal width, the patent achieves both high substrate area utilization and adequate mechanical strength.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12520420B2Wiring substrate

Publication Date: 2026.01.06 IBIDEN CO LTD

AI summary

A wiring substrate includes an insulating layer, and a conductor layer including a wiring formed on the insulating layer. The wiring in the conductor layer has a first section and a second section formed such that a wiring width in the second section is smaller than a wiring width in the first section and that a wiring thickness in the second section is larger than a wiring thickness in the first section.