Copper Electroplating Bath with Alkyl Diamine Additive

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Solution Overview

Problem

Copper electroforms produced using rotating cylinder mandrels often have high oxygen content, which adversely affects their mechanical and electrical properties, and existing methods to reduce oxygen content are either difficult to control or leave residual impurities.

Innovation Solution

A copper electroplating bath comprising a soluble copper salt, acidic electrolyte, and a grain refining additive such as alkyl diamine, combined with brighteners and de-aeration techniques to minimize oxygen incorporation, allowing for the production of copper deposits with low oxygen content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional additives (polyether molecules and sulfopropyl sulfides) are used in sulfate and fluoroborate electrolytes, then deposit nodulation is prevented and mechanical properties are improved, but oxygen content in the copper electroforms increases to unacceptable levels (up to 500 ppm)

Engineering Contradiction:

Improvemechanical propertiesVSAvoidoxygen content

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters of the plating bath by replacing conventional polyether and sulfide additives with specific alternative additives (sulfonated polyether molecules with specific structural formulas). This parameter change maintains the ability to prevent deposit nodulation and ensure mechanical properties while reducing oxygen incorporation in the copper deposit to below 10 ppm.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses alternative additives that serve the same functional purpose as conventional additives but with the critical difference of not introducing oxygen into the deposit. These additives are designed to be effective at lower concentrations and can be used without the harmful oxygen incorporation side effect of traditional polyether and sulfide-based additives.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If remelting under controlled reducing atmosphere is used to reduce oxygen content, then oxygen level is reduced, but the process becomes difficult to control and may leave residual impurities

Engineering Contradiction:

Improveoxygen contentVSAvoidprocess control complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention applies preliminary action by preventing oxygen incorporation during the electrodeposition process itself through the use of specially formulated additives. This approach eliminates the need for subsequent remelting or deoxidation treatments, thereby avoiding the complexity of controlling reducing atmospheres and the risk of introducing residual impurities from deoxidizing agents.

Inventive Principle:

Principle #10Preliminary action

3Object-affected harmful factors

If deoxidizing agents (phosphorus, boron, lithium) are added to molten copper, then oxygen content is reduced, but dissolved reducing metal remains in the copper adversely affecting properties

Engineering Contradiction:

Improveoxygen contentVSAvoidcopper properties

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention converts the harmful effect of oxygen incorporation during electrodeposition into a beneficial outcome by using alternative additives that prevent oxygen uptake in the first place. This approach avoids the need to use deoxidizing agents that would otherwise be necessary to remove oxygen, thereby preventing the introduction of residual reducing metal impurities that would compromise copper properties.

Inventive Principle:

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

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 solution effectively reduces oxygen content in copper electroforms to below 10 ppm, enhancing their ductility, conductivity, and mechanical properties while avoiding residual impurities, making them suitable for applications requiring low oxygen levels.

Implementation Method 1

Electroplating methods involve passing a current between two electrodes in a plating solution where one electrode is the article to be plated

Methodology Applied

Scientific EffectElectrodeposition: Electrodeposition

Implementation Method 2

combined with brighteners and de-aeration techniques to minimize oxygen incorporation

Methodology Applied

Scientific EffectDe-aeration:

Data Source

PatentEP2855738B1Additives for producing copper electrodeposits having low oxygen content

Publication Date: 2022.07.06 MACDERMID ACUMEN INC

AI summary

A copper electroplating bath for producing copper electrodeposits is described, The copper electroplating bath comprises (a) a soluble copper salt, (b) an electrolyte comprising one or more acids, and (c) a grain refining additive comprising an alkyl5 aryl or atkylaryl diamine. The copper electroplating bath can be used for producing eleetroformed copper deposits having low oxygen content,