Electroless Platinum Plating Solution Stability and Selectivity
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Solution Overview
Problem
Existing electroless platinum plating solutions face challenges in achieving high deposition efficiency, preventing out-of-pattern deposition, and producing a pure platinum film without sulfur or heavy metal impurities, as previous solutions either decompose quickly, have low plating speed, or fail to suppress unwanted deposition effectively.
Innovation Solution
An electroless platinum plating solution with a pH of 7 or more, containing a soluble platinum salt, a complexing agent, and a reducing agent such as borohydride, aminoborane, or hydrazine, combined with a specific hydroxymethyl compound, which allows for high-speed and high-efficiency plating while minimizing impurities and out-of-pattern deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a thiol compound is used as an additive to suppress self-decomposition of the plating solution, then the stability of the plating solution is improved, but the plating speed becomes low and sulfur co-deposits in the platinum plating film
Solution Approach 1:
The patent removes thiol compounds and other sulfur-containing stabilizers from the plating solution formulation. Instead, it uses a novel stabilizer system comprising a polyamine compound (specifically diethylenetriamine or triethylenetetramine) combined with a borohydride compound, which eliminates sulfur co-deposition while maintaining solution stability and high plating speed.
Solution Approach 2:
The patent changes the chemical parameters of the stabilizer system by replacing sulfur-based compounds with nitrogen-based polyamine compounds. This parameter change maintains the stabilizing function while eliminating the harmful side effects of sulfur co-deposition and low plating speed.
2Stability of the object's composition
If thallium ions or tellurium ions are added as stabilizers to prevent decomposition and suppress out-of-pattern deposition, then the stability is improved, but heavy metals co-deposit in the platinum plating film reducing purity
Solution Approach 1:
The patent extracts and eliminates thallium ions and tellurium ions from the plating solution. These heavy metal stabilizers are replaced with a non-toxic, heavy-metal-free stabilizer system using polyamine compounds (diethylenetriamine or triethylenetetramine) combined with borohydride, which maintains stability without compromising film purity.
3Manufacturing precision
If a nitro compound is added as an oxidizing agent to suppress out-of-pattern deposition, then the pattern selectivity is improved, but the effect is insufficient and cannot fully prevent unwanted deposition
Solution Approach 1:
The patent changes the oxidizing agent from a nitro compound to an ozone-based system. Ozone is introduced into the plating solution, where it oxidizes the catalyst layer selectively, enhancing pattern selectivity and effectively suppressing out-of-pattern deposition. This parameter change provides superior and more reliable deposition control compared to nitro compounds.
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 stable, high-yield platinum plating with reduced production costs, minimal impurities, and improved pattern selectivity, forming high-purity platinum films on ceramics without cracks or pinholes, thus addressing the limitations of previous technologies.
Implementation Method 1
containing a soluble platinum salt, a complexing agent, and a reducing agent that is any of a borohydride compound, an aminoborane compound, and a hydrazine compound
Implementation Method 2
containing a soluble platinum salt, a complexing agent, and a reducing agent
Data Source
AI summary
An electroless platinum plating solution is disclosed that can be subjected to plating processing with high deposition efficiency, does not self-decompose even when it does not contain sulfur or heavy metals, and has excellent bath stability, and an electroless platinum plating solution that can suppresses out-of-pattern deposition of platinum and perform platinum plating only on a necessary portion. An electroless platinum plating solution is disclosed that contains a soluble platinum salt, a complexing agent and any of a borohydride compound, an aminoborane compound and a hydrazine compound, and has a pH of 7 or more, adding a specific hydroxymethyl compound represented by the following formula (1) or a salt thereof:R1—CH2—OH (1)wherein R1 is an atomic group having an aldehyde group or a ketone group.