Lead-Free Glass Composition for Low-Temperature Adhesion

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional glass compositions used in electronic components, such as solar cell panels and display devices, often contain environmentally hazardous materials like lead, bismuth, and antimony, which are restricted by regulations like the RoHS directive, and may suffer from moisture-induced corrosion and high costs due to the use of rare metals like tellurium.

Innovation Solution

A glass composition comprising phosphorus, vanadium, and transition metals like tungsten, iron, and manganese, with specific oxide ratios, that softens and melts at 500-600°C, avoiding JIG level A and B substances and ensuring reliable adhesion and moisture resistance without using lead, bismuth, or antimony.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lead-containing glass composition is used, then adhesion and low-temperature softening are achieved, but environmental safety deteriorates

Engineering Contradiction:

ImproveadhesionVSAvoidenvironmental safety

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by replacing lead oxide with zinc oxide and boron oxide, adjusting the oxide ratios to achieve both environmental compliance and functional performance. Specifically, zinc oxide (40-70 wt%) and boron oxide (10-30 wt%) are used to lower the softening temperature while maintaining adhesion properties without lead content.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite glass composition combining multiple metal oxides (zinc oxide, boron oxide, silicon oxide, aluminum oxide) to achieve the desired properties. This composite approach allows the material to exhibit both environmental safety and functional characteristics of low-temperature softening and strong adhesion that individual oxides cannot provide alone.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If bismuth oxide or antimony oxide is used as lead-free alternative, then environmental safety improves, but adhesion and moisture resistance deteriorate

Engineering Contradiction:

Improveenvironmental safetyVSAvoidadhesion and moisture resistance

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the compositional parameters by eliminating bismuth oxide and antimony oxide entirely, replacing them with zinc oxide and boron oxide in specific ratios. This parameter change ensures both environmental compliance (avoiding JIG level A and B substances) and functional reliability (adhesion and moisture resistance through zinc oxide's protective properties).

Inventive Principle:

Principle #35Parameter changes

3Temperature

If tellurium is used to achieve low softening point, then softening temperature improves, but cost and environmental safety deteriorate

Engineering Contradiction:

Improvesoftening temperatureVSAvoidcost and environmental safety

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the compositional parameters by replacing tellurium oxide with boron oxide and zinc oxide. Boron oxide (10-30 wt%) provides the low-temperature softening capability traditionally associated with tellurium, while zinc oxide adds environmental safety and cost-effectiveness. This parameter substitution achieves the same functional result without the harmful and expensive tellurium metal.

Inventive Principle:

Principle #35Parameter changes

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 glass composition provides a cost-effective, environmentally friendly solution for electronic components, ensuring reliable adhesion and moisture resistance while complying with environmental regulations, and maintaining performance comparable to conventional low-softening-point glass compositions.

Implementation Method 1

a glass composition including: phosphorus; vanadium; and at least one transition metal selected from a group consisting of tungsten, iron, and manganese, the glass composition not containing substances included in the JIG level A and B lists, a softening point of the glass composition being 550° C. or lower

Methodology Applied

Scientific EffectSoftening:

Implementation Method 2

the glass composition softens and melts at 500-600°C

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

By this firing process, the interconnection member becomes formed of a dense material and also strongly adheres to the substrate

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 4

ensuring reliable adhesion and moisture resistance

Methodology Applied

Scientific EffectCorrosion resistance:

Data Source

PatentUS8895460B2Glass composition, electrically conductive paste composition comprising same, electrode wiring member, and electronic component

Publication Date: 2014.11.25 RESONAC CORP

AI summary

A glass composition according to the present invention comprises: phosphorus, vanadium and at least one transition metal selected from a group consisting of tungsten, iron, and manganese, the glass composition not containing substances included in the JIG level A and B lists, a softening point of the glass composition being 550° C. or lower.