Magnetic Ceramic Substrate Glass Composition for Plating Adhesion

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Solution Overview

Problem

Existing magnetic ceramic substrates face challenges with adhesion between the ceramic substrate and conductor patterns, particularly under thermal stress, and suffer from degraded plating adhesion due to excessive glass content in conductor pastes.

Innovation Solution

A magnetic ceramic substrate with a smooth base material surface and a conductor pattern containing amorphous glass, which improves adhesion without adversely affecting plating adhesion, is developed. The amorphous glass is dispersed within the metal conductor and fused to enhance binding strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conductor paste containing a large amount of glass frit is used to improve adhesion, then adhesion between the conductor pattern and the ceramic substrate is improved, but plating adhesion on the conductor surface deteriorates

Engineering Contradiction:

Improveadhesion between conductor pattern and ceramic substrateVSAvoidplating adhesion on conductor surface

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the glass frit by specifying precise ranges: SiO2 (30-70 wt%), Al2O3 (5-40 wt%), B2O3 (5-30 wt%), and controlling Fe2O3 content below 5 wt%. This optimized composition provides sufficient adhesion while maintaining a smooth conductor surface that supports good plating adhesion, resolving the contradiction between adhesion strength and plating quality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite conductor paste formulation combining metal particles with a specifically formulated glass frit matrix. The glass frit acts as a bonding agent that chemically bonds to the ceramic substrate while the metal particles provide conductivity. The composite structure achieves both strong adhesion and good plating characteristics through the synergistic combination of materials.

Inventive Principle:

Principle #40Composite materials

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

This configuration achieves excellent adhesion between the conductor pattern and the base material while maintaining good plating adhesion on the conductor pattern, reducing thermal stress-induced cracks and improving overall reliability.

Implementation Method 1

a conductor pattern containing a metal conductor and amorphous glass

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

the amorphous glass is dispersed within the metal conductor and fused to enhance binding strength

Methodology Applied

Scientific EffectGlass fusion: Melting

Implementation Method 3

the surface of the base material is smooth... reduces thermal stress-induced cracks

Methodology Applied

Scientific EffectStress distribution: Stress Relaxation

Data Source

PatentUS20250016919A1Magnetic ceramic substrate, substrate manufacturing method, and circulator

Publication Date: 2025.01.09 MITSUBISHI ELECTRIC CORP

AI summary

A magnetic ceramic substrate includes a base material made of magnetic ceramic and a conductor pattern formed to be in contact with a surface of the base material. The surface of the base material is smooth, and the conductor pattern contains a metal conductor and amorphous glass. A circulator includes the magnetic ceramic substrate.