Tin Oxide Multilayer Film for Uniform Catalyst Deposition
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Solution Overview
Problem
Existing methods for forming metal films on non-conductive substrates using electroless plating result in uneven and poorly adherent films due to the oxidation of divalent tin ions to tetravalent tin ions, leading to uneven catalyst layers and low adhesion forces.
Innovation Solution
A method involving the formation of a stable divalent tin solution by dissolving a tin compound in a polar solvent with a fluoride solution, followed by immersion in a catalyst solution to create a thick and uniform tin oxide multilayer film with a catalyst layer, ensuring a thickness of 2 nm to 60 nm and a developed interfacial area ratio of less than 1×10−4.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin tin oxide layer is formed by immersing substrate in divalent tin source for several minutes, then the sensitizer treatment is completed, but the catalyst layer becomes uneven and adhesion force decreases
Solution Approach 1:
The patent changes the concentration parameters of the tin source solution and extends the immersion time from several minutes to several hours. This parameter change transforms the tin oxide layer from thin and scattered to thick and uniform, enabling proper catalyst support and achieving both uniformity and strong adhesion force for the metal film.
2Ease of manufacture
If divalent tin ions are used in aqueous solution, then tin oxide layer can be formed, but divalent tin ions are oxidized to tetravalent tin ions by dissolved oxygen, forming SnO2 precipitates that cause unevenness
Solution Approach 1:
The patent creates an inert environment by thoroughly deaerating the aqueous solution to remove dissolved oxygen before adding the divalent tin source. This prevents oxidation of divalent tin ions to tetravalent tin ions, eliminating SnO2 precipitate formation and ensuring a uniform tin oxide layer.
Solution Approach 2:
The patent performs preliminary deaeration of the solution before introducing the tin source. This preliminary action removes dissolved oxygen in advance, preventing subsequent oxidation reactions that would cause unevenness in the tin oxide layer.
3Quantity of substance
If SnO2 precipitates are formed in the solution, then tetravalent tin ions are produced, but the precipitates attach as lumps to the substrate surface causing severe unevenness
Solution Approach 1:
The patent maintains an inert environment throughout the process by keeping the solution deaerated. This prevents the formation of SnO2 precipitates entirely, ensuring that tin oxide is formed uniformly as a adherent layer rather than as lumped precipitates on the substrate surface.
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 method produces a uniform and adherent tin oxide multilayer film with a catalyst layer, enhancing the adhesion force and reducing unevenness, allowing for stable electroless plating.
Implementation Method 1
divalent tin ions are oxidized into tetravalent tin ions by dissolved oxygen in water serving as a medium, forming SnO2
Implementation Method 2
a layer of tin oxide is extremely thin and scattered
Data Source
AI summary
A method for forming a tin oxide multilayer film with a catalyst layer, the method including preparing a concentrated liquid in which a tin compound is dissolved in a polar solvent; diluting the concentrated liquid with the polar solvent and a fluoride solution to prepare a reaction liquid that is a stable divalent tin solution; immersing a substance to be treated in the reaction liquid to form a tin oxide layer on a surface of the substance to be treated; and immersing the substance to be treated having the tin oxide layer formed on the surface in a catalyst solution containing catalyst metal ions to form a catalyst layer on the tin oxide layer.