Swelled Circuit Conductor Profile for High-Current Dense Layouts

Solution Overview

Problem

Existing circuit patterns with swelled shapes in the layer-crossing direction at intermediate portions tend to cause short circuits and ion migration between adjacent conductors, limiting their application to large current capacities and tight arrangements.

Innovation Solution

A circuit pattern with a swelled shape in the layer-crossing direction formed by a gentle face in the layer direction, achieved through a production method involving double-side etching to connect circuit conductors with thin connection portions and subsequent single-side etching to form a swelled shape with a gentle face, layered on an insulating layer and metal substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If double-side etching is performed to form a swelled shape at the intermediate portion, then the sectional area of the circuit conductor is increased for large current application, but the intermediate portion becomes sharply pointed causing short circuit and ion migration between adjacent conductors

Engineering Contradiction:

Improvesectional area of circuit conductorVSAvoidshort circuit and ion migration resistance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The invention applies different etching processes to different regions of the circuit conductor. The intermediate portion (requiring large sectional area) is treated with double-side etching to create swelled shape, while the top portion (requiring reliability) is treated with single-side etching to create a tapered shape with wider top. This local differentiation of etching quality resolves the contradiction between maximizing current capacity and preventing short circuits.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The etching process is segmented into two distinct stages: first, double-side etching is performed to create the swelled intermediate portion for large current capacity; second, single-side etching is performed to create the tapered top portion for reliability. This segmentation of the manufacturing process allows each region to have optimized geometry for its specific functional requirement.

Inventive Principle:

Principle #1Segmentation

2Reliability

If single-side etching is performed to form a tapered shape with wider top, then the reliability against disconnection is improved, but the sectional area of the circuit conductor is limited restricting application to large current

Engineering Contradiction:

Improvedisconnection resistanceVSAvoidsectional area of circuit conductor

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The etching process is segmented into two distinct stages: first, double-side etching is performed to create the swelled intermediate portion for large current capacity; second, single-side etching is performed to create the tapered top portion for reliability. This segmentation of the manufacturing process allows each region to have optimized geometry for its specific functional requirement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention applies different etching processes to different regions of the circuit conductor. The intermediate portion (requiring large sectional area) is treated with double-side etching to create swelled shape, while the top portion (requiring reliability) is treated with single-side etching to create a tapered shape with wider top. This local differentiation of etching quality resolves the contradiction between maximizing current capacity and preventing short circuits.

Inventive Principle:

Principle #3Local quality

3Productivity

If circuit conductors are arranged tightly to increase productivity, then the space utilization is improved, but the risk of short circuit and ion migration between adjacent conductors increases

Engineering Contradiction:

Improvespace utilizationVSAvoidshort circuit and ion migration resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention applies different etching processes to different regions of the circuit conductor. The intermediate portion (requiring large sectional area) is treated with double-side etching to create swelled shape, while the top portion (requiring reliability) is treated with single-side etching to create a tapered shape with wider top. This local differentiation of etching quality resolves the contradiction between maximizing current capacity and preventing short circuits.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12484144B2Circuit pattern, semi-finished base material for circuit substrate, metal-based circuit substrate, production method for circuit pattern, and production device for circuit pattern

Publication Date: 2025.11.25 NHK SPRING CO LTD

AI summary

A circuit pattern is obtained, capable of being easily applicable to current increase, making short circuit or ion migration between adjacent circuit conductors hard to be generated, and allowing a circuit pattern to be tightly arranged. A circuit pattern comprises a circuit conductor to be layered on a metal substrate through an insulating layer, an intermediate portion in a layer direction having a swelled shape in a layer-crossing direction in a cross section of the circuit conductor, and the swelled shape is formed by a gentle face in the layer direction.