Oxygen Aeration for Copper Etching Solution Regeneration

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Solution Overview

Problem

Conventional copper etching processes in printed circuit board production rely on aggressive oxidizing agents like hydrogen peroxide, which pose environmental and health risks, and require improved regeneration methods for copper etching solutions.

Innovation Solution

A process that introduces oxygen gas or air into an acidic reduced copper etching solution, generating bubbles for enhanced mass transfer and oxidation, resulting in an oxidized copper etching solution with improved etching efficiency and environmental safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If aggressive oxidizing agents like hydrogen peroxide are used to regenerate copper etching solution, then oxidation efficiency is improved, but environmental harm and health risks increase

Engineering Contradiction:
Improveoxidation efficiencyVSAvoidenvironmental harm
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the oxidation method from chemical oxidation using aggressive agents to electrochemical oxidation using electrodes. This parameter change transforms the oxidation process into an electrochemical reaction that occurs at the electrode surface, eliminating the need for harmful chemical oxidizing agents while maintaining high oxidation efficiency for regenerating copper etching solution

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the chemical oxidation system with an electrochemical system. Instead of using chemical oxidizing agents like hydrogen peroxide or ozone, the patent employs electrical energy to drive the oxidation reaction at electrodes, substituting a chemical process with an electrochemical one that is environmentally friendly

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Quantity of substance

If oxygen gas is introduced into copper etching solution to form bubbles, then mass transfer area is increased, but process complexity increases

Engineering Contradiction:
Improvemass transfer areaVSAvoidprocess complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The invention merges the gas introduction function with the existing circulation system. Oxygen gas is introduced into the copper etching solution through the circulation loop, combining the aeration function with the existing fluid circulation infrastructure, thereby increasing mass transfer area without significantly increasing process complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The circulation system naturally distributes oxygen bubbles throughout the solution as it flows through the circulation loop. The system uses its own circulation mechanism to achieve uniform gas distribution, eliminating the need for additional complex gas distribution equipment

Inventive Principle:
Principle #25Self-service

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 process achieves faster and more efficient copper oxidation with a straighter vertical profile on printed circuit boards, reducing harmful emissions and offering significant cost savings while improving working conditions and etching quality.

Implementation Method 1

introducing the oxidizing agent into an acidic reduced copper etching solution, generating bubbles

Methodology Applied
Scientific EffectBubble formation: Bubble

Implementation Method 2

facilitating mass transfer of oxygen from oxygen gas and/or air into the liquid solution

Methodology Applied
Scientific EffectMass transfer: Diffusion

Implementation Method 3

oxidizing copper in a copper etching solution by using oxygen gas and/or air as an oxidizing agent

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 4

the oxidation reaction to occur

Methodology Applied
Scientific EffectRedox reaction: Redox Reactions

Data Source

PatentEP3126544B1Oxidation of copper in a copper etching solution by the use of oxygen and/or air as an oxidizing agent
Publication Date: 2019.07.24 SIGMA ENG AB
  • EP3126544B1 patent drawingFigure 1
  • EP3126544B1 patent drawingFigure 2~3
  • EP3126544B1 patent drawingFigure 4

AI summary

The present invention relates to a process of oxidizing copper in a copper etching solution by using oxygen gas and/or air as an oxidizing agent, the process comprising the steps of: a) introducing the oxidizing agent into an acidic reduced copper etching solution comprising CI- and Cu+, b) stirring the solution obtained in step a), and thereby allowing the reaction 2 Cu+ + ½ O2 (aq) + 2 H+→ 2 Cu2+ + H2O to occur, thereby producing an oxidized copper etching solution comprising less Cu+ than the reduced copper etching solution. An advantage of the present invention is that it provides an improved process at least in terms of the speed of the oxidation and the quality of the etching.