Halogen-Free Electroless Plating Bath Using Tetraammine Complexes
Solution Overview
Problem
Conventional electroless plating baths containing halides, such as chloride, bromide, and fluoride, cause corrosion of substrates and underlying metals during plating, necessitating the development of a halogen-free electroless plating bath for improved reliability in electronic parts.
Innovation Solution
A halogen-free electroless plating bath comprising a water-soluble platinum or palladium compound, specifically tetraammine platinum (II) or palladium (II) complex salts without halides, and a reducing agent like formic acid, which maintains stability and prevents halide-derived corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If halides such as chloride are contained in the electroless plating bath to improve bath stability, then electroless plating bath stability is improved, but substrate corrosion occurs during plating treatment
Solution Approach 1:
The patent removes halide components (chloride, bromide, fluoride) from the electroless plating bath composition entirely. By extracting the harmful halide stabilizers and replacing them with halogen-free alternatives, the invention eliminates substrate corrosion while maintaining bath stability through different chemical mechanisms.
Solution Approach 2:
The patent changes the chemical composition parameters of the plating bath by using specific platinum or palladium complexes with non-halide ligands (such as ammonia, amine, or carboxylate ligands) and employing non-halide stabilizing agents. This parameter change from halide-based to halogen-free chemistry resolves the contradiction between stability and corrosion prevention.
2Stability of the object's composition
If halides are used as additives in the electroless plating bath to maintain bath stability, then deposition control is improved, but plating film purity is reduced due to halide contamination
Solution Approach 1:
The invention extracts and eliminates halide additives from the plating bath formulation. By removing sources of halide contamination (such as halide-containing stabilizers and complexing agents), the patent produces high-purity plating films without compromising bath stability through the use of halogen-free chemical systems.
Solution Approach 2:
The patent changes the chemical parameters by selecting metal complexes with non-halide ligands and using stabilizing agents that do not introduce halogen. This parameter transformation from halide-based to halogen-free chemistry ensures both bath stability and plating film purity simultaneously.
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 enables excellent plating film deposition without halide contamination, enhancing electroless plating bath stability and preventing substrate corrosion, thus ensuring reliable plating films for electronic components.
Implementation Method 1
a reducing agent wherein the reducing agent is formic acid or its salts
Data Source
AI summary
An object of the present invention is to provide an electroless plating bath having excellent property in plating film deposition without containing halides such as chloride in the electroless plating bath. A halogen-free electroless plating bath of the present invention comprising:a water soluble platinum compound ora water soluble palladium compound, anda reducing agent whereinthe water soluble platinum compound is a tetraammine platinum (II) complex salt excluding a halide of the tetraammine platinum (II) complex salt,the water soluble palladium compound is a tetraammine palladium (II) complex salt excluding a halide of the tetraammine palladium (II) complex salt and tetraammine palladium (II) sulfate,the reducing agent is formic acid or its salts, andthe electroless plating bath contains no halide as an additive.