Solder Material with In-Situ Oxide Reduction for Residue-Free Bonding

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Solution Overview

Problem

Existing soldering pastes require complex mixtures of chemicals and often necessitate a reducing atmosphere in a furnace, which can be costly and environmentally hazardous.

Innovation Solution

A solder material comprising metal solder particles and a reducing tacking agent, such as a combination of a carboxylic acid and an alcohol, that generates a reducing agent in situ during the soldering process, eliminating the need for a hazardous atmosphere and complex chemical mixtures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex chemical mixtures (flux systems) are used in soldering pastes, then soldering effectiveness is improved, but environmental safety and simplicity deteriorate

Engineering Contradiction:

Improvesoldering effectivenessVSAvoidenvironmental safety

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the complex flux system (containing thickener, activators, tensides, and other chemicals) from the solder paste, retaining only the essential metal powder and volatile liquid components. This extraction removes harmful chemicals while preserving the core soldering function through intrinsic reducing agent generation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the typically harmful role of flux systems into a beneficial intrinsic reducing mechanism. The volatile liquid (alcohol) and carboxylic acid components naturally generate reducing agents during heating that effectively reduce metal oxides without requiring hazardous chemical fluxes, thus converting potential harm into benefit.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If reducing atmosphere in furnace is used, then oxide reduction is improved, but cost and environmental safety deteriorate

Engineering Contradiction:

Improveoxide reductionVSAvoidenvironmental safety

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The solder paste becomes self-sufficient by containing its own reducing agent generation system. The volatile liquid and carboxylic acid in the paste naturally produce reducing agents during the soldering process, eliminating the need for external reducing atmosphere from the furnace and making the process environmentally safe.

Inventive Principle:

Principle #25Self-service

3Reliability

If reducing atmosphere in furnace is used, then oxide reduction is improved, but device complexity deteriorate

Engineering Contradiction:

Improveoxide reductionVSAvoidfurnace requirements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the reducing atmosphere function from the furnace system and relocates it into the solder paste itself. This eliminates the need for complex furnace equipment capable of providing controlled reducing atmospheres, simplifying the overall soldering system while maintaining effective oxide reduction.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If complex chemical mixtures are used, then soldering functionality is improved, but manufacturing simplicity deteriorates

Engineering Contradiction:

Improvesoldering functionalityVSAvoidmanufacturing simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the unnecessary complex chemical components (thickeners, activators, tensides) from the solder paste formulation, leaving only the essential metal powder and volatile liquid mixture. This simplification makes manufacturing more straightforward while preserving all necessary soldering functionalities through the intrinsic chemistry of the remaining components.

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 solder material achieves effective oxide reduction and bonding without the need for a reducing furnace atmosphere, resulting in a residue-free, lead-free solder layer that is environmentally friendly and cost-effective.

Implementation Method 1

a carboxylic acid and an alcohol selected from the group consisting of methanol, ethanol, propan-1-ol, propan-2-ol, 2-methyl-1-propanol, butan-1-ol, pentan-1-ol, 1,2-propanediol, 1,3-propanediol, and glycerol

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

generates a reducing agent in situ during the soldering process, eliminating the need for a hazardous atmosphere

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 3

heating at least the solder material to a melting temperature of the metal solder particles

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 4

heating at least the solder material to a melting temperature of the metal solder particles

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS20250100088A1Solder material, layer structure, and method of forming a layer structure

Publication Date: 2025.03.27 INFINEON TECHNOLOGIES AG

AI summary

A solder material is provided. In one or more examples, the solder material may include metal solder particles, a carboxylic acid, and an alcohol selected from the group consisting of methanol, ethanol, propan-1-ol, propan-2-ol, 2-methyl-1-propanol, butan-1-ol, pentan-1-ol, 1,2-propanediol, 1,3-propanediol, and glycerol.