Low-Temperature Sintering Ceramic Substrate Composition

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Solution Overview

Problem

Low-temperature sintering ceramic materials without glass and boron are needed to achieve high strength and reliable bonding with external conductor films, while avoiding composition variation and simplifying the firing process.

Innovation Solution

A ceramic material composition featuring 48-75% SiO2, 20-40% BaO, 5-20% Al2O3, with accessory constituents including 2-10% MnO, 0.1-10% TiO2, and 0.1-5% Fe2O3, excluding Cr and B oxides, and optionally MgO, to enhance sintering and bonding strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If glass is used as a starting material for low-temperature sintering ceramic, then sintering temperature can be reduced, but composition variation increases and management becomes complicated due to boron volatilization

Engineering Contradiction:
Improvesintering temperatureVSAvoidcomposition variation
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The invention extracts and eliminates boron-containing glass components from the ceramic composition, replacing them with a glass-free system using metal oxides (SiO2, BaO, Al2O3) and accessory constituents (MnO, TiO2, Fe2O3, MgO). This removal of the problematic glass phase eliminates boron volatilization while maintaining low-temperature sintering capability through alternative sintering mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical composition parameters by defining specific ranges: SiO2 (48-75 wt%), BaO (20-40 wt%), Al2O3 (5-20 wt%), MnO (2-10 wt%), TiO2 (0.1-10 wt%), Fe2O3 (0.1-10 wt%), and MgO (0.1-5 wt%). These parameter changes create a stable, glass-free composition that sinters at low temperatures without boron volatilization issues.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If conventional low-temperature sintering ceramic materials are used, then sintering temperature is reduced, but bending strength becomes insufficient (150-200 MPa)

Engineering Contradiction:
Improvesintering temperatureVSAvoidbending strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The invention creates a composite ceramic material system combining multiple metal oxides (SiO2, BaO, Al2O3) with accessory constituents (MnO, TiO2, Fe2O3, MgO). This composite composition achieves synergistic effects where MnO and TiO2/Fe2O3 promote low-temperature sintering while MgO and the base ceramic phase provide structural strength, resulting in bending strength exceeding 200 MPa.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention optimizes composition parameters within specific ranges: SiO2 (48-75 wt%), BaO (20-40 wt%), Al2O3 (5-20 wt%), MnO (2-10 wt%), TiO2 (0.1-10 wt%), Fe2O3 (0.1-10 wt%), and MgO (0.1-5 wt%). These parameter changes enable the material to achieve both low-temperature sintering and high bending strength by balancing phases that promote sintering with those that provide mechanical strength.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If conventional low-temperature sintering ceramic materials are used, then sintering temperature is reduced, but bonding strength with external conductor film becomes insufficient

Engineering Contradiction:
Improvesintering temperatureVSAvoidbonding strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The invention optimizes surface composition parameters by controlling the presence of MnO (2-10 wt%), TiO2 (0.1-10 wt%), and Fe2O3 (0.1-10 wt%) on the ceramic surface. These accessory constituents create a chemically active surface that enhances wetting and bonding with external conductor films such as silver or copper, achieving strong adhesion at low sintering temperatures without requiring additional bonding treatments.

Inventive Principle:
Principle #35Parameter changes

4Temperature

If glass is used as starting material, then low-temperature sintering is achieved, but expensive glass and special sagger are required

Engineering Contradiction:
Improvesintering temperatureVSAvoidmanufacturing cost and complexity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates expensive glass materials and the associated special sagger requirements from the manufacturing process. By using a glass-free composition of common metal oxides (SiO2, BaO, Al2O3) with accessory constituents, the material can be processed using conventional ceramic manufacturing techniques and standard firing atmospheres, significantly reducing material costs and manufacturing complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

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

The ceramic substrate exhibits high bending strength, excellent electrode peel strength, and improved environmental and chemical tolerance, with reduced firing variation and no need for special sagger use, facilitating mass production and stable glass formation without expensive glass.

Implementation Method 1

low-temperature sintering ceramic material

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP2386528B1Ceramic material for low-temperature sintering, and ceramic substrate
Publication Date: 2016.08.24 MURATA MFG CO LTD
  • EP2386528B1 patent drawingFigure 1~2

AI summary

There is provided a low-temperature sintering ceramic material showing little variation in composition after firing, realizing high bending strength in a sintered body, and capable of forming a reliable ceramic substrate showing high peel strength of a surface electrode. A low-temperature sintering ceramic material used for constituting a ceramic layer (2) of a multilayer ceramic substrate (1) includes a main constituent ceramic material containing 48 to 75 weight% in terms of SiO2 of Si, 20 to 40 weight% in terms of BaO of Ba, and 5 to 20 weight% in terms of Al2O3 of Al, and an accessory constituent ceramic material containing, relative to 100 parts by weight of the main constituent ceramic material, 2 to 10 parts by weight in terms of MnO of Mn and 0.1 to 10 parts by weight respectively in terms of TiO2 and Fe2O3 of at least one selected from Ti and Fe, and substantially not includes both Cr oxide and B oxide.