Copper-Silver Plating Film Methionine Complexing Agent
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Solution Overview
Problem
Copper electrolytic plating films with silver alloy components face issues of sulfur co-deposition when using thiourea as a complexing agent, leading to deterioration of physical properties and corrosion resistance, especially after high-temperature heat treatments.
Innovation Solution
A copper electrolytic plating bath containing silver ions and methionine or its derivatives as a complexing agent, which suppresses sulfur co-deposition and maintains columnar crystal structure and high mechanical properties even after heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thiourea is used as a complexing agent to stabilize silver ions, then silver chloride precipitation is prevented, but sulfur is co-deposited in the plating film causing deterioration of physical properties and corrosion resistance
Solution Approach 1:
The patent changes the chemical parameter of the complexing agent from thiourea (sulfur-containing) to methionine or its derivatives (with controlled sulfur content), thereby altering the deposition behavior to reduce sulfur co-deposition while maintaining silver ion stabilization
Solution Approach 2:
The patent uses methionine or its derivatives as a temporary complexing agent that forms stable complexes during plating but does not lead to harmful sulfur co-deposition, effectively replacing the problematic thiourea
2Temperature
If copper plating film is subjected to high-temperature heat treatment, then resin film curing is achieved, but recrystallization occurs causing significant decrease in hardness and tensile strength
Solution Approach 1:
The patent creates a copper-silver alloy plating film where silver acts as a strengthening phase within the copper matrix, suppressing recrystallization during heat treatment and maintaining mechanical properties
Solution Approach 2:
The patent introduces silver particles distributed locally within the copper plating film structure, creating regions with different crystallization behavior that collectively resist recrystallization during heat treatment
3Length of moving object
If copper plating film thickness is reduced for downsizing, then higher density mounting is achieved, but strength and hardness of the plating film decrease
Solution Approach 1:
The patent uses copper-silver alloy composition where silver reinforces the copper matrix, enabling thin plating films to maintain high strength and hardness through alloy strengthening mechanisms
Solution Approach 2:
The patent changes the compositional parameter by adding silver alloying elements to the copper plating bath, fundamentally altering the mechanical properties to achieve high strength in thin films
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 results in a copper electrolytic plating film with enhanced strength and hardness, significantly reducing sulfur content and preventing embrittlement, making it suitable for electronic device components even after high-temperature exposure.
Implementation Method 1
methionine or a derivative thereof is contained as the complexing agent
Implementation Method 2
copper electrolytic plating is widely used in the electronics industry as surface treatment
Implementation Method 3
silver chloride is generally precipitated by a reaction with chloride ions, and hence, in order to stabilize silver and prevent precipitation of silver chloride
Implementation Method 4
if the copper plating film is allowed to stand at room temperature after plating, recrystallization occurs in a few hours to several days, and the crystal size increases whereby the copper plating film softens
Data Source
AI summary
The present invention provides a technology for, in copper electrolytic plating containing silver ions as an alloy component, obtaining a copper electrolytic plating film in which co-deposition of sulfur can be significantly suppressed and which is excellent in physical properties such as strength and hardness even after a high-temperature heat treatment at about 200° C. or higher. The present invention is a copper electrolytic plating bath comprising copper ions, an acid, chloride ions, and a complexing agent, wherein the copper electrolytic plating bath further comprises silver ions as an alloy component, and wherein methionine or a derivative thereof is contained as the complexing agent.