Metal Surface Treatment Composition for PCB Adhesion
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Solution Overview
Problem
The existing methods for treating metal surfaces, such as copper and copper alloys, in printed circuit boards fail to provide strong adhesion to polymeric materials, leading to delamination issues in multilayer composites.
Innovation Solution
A composition comprising an oxidizer, an acid, a source of halide ions, and poly(ethyleneamino propionitrile) polymer is used to roughen the metal surfaces, enhancing the adhesion of polymeric materials to metal surfaces during the manufacturing of printed circuit boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional chemical oxidation or microetching compositions are used to treat copper surfaces, then the surface is roughened to some extent, but the adhesion strength to polymeric materials remains insufficient
Solution Approach 1:
The patent uses a composite etching composition containing multiple active agents (ferric ion source, cupric ion source, organic acid, inorganic acid, halide ion source) working synergistically. This composite approach creates a more effective surface treatment than single-agent systems, producing both surface roughening and chemical activation that together provide superior adhesion strength and delamination resistance.
Solution Approach 2:
The patent systematically varies composition parameters (concentrations of ferric ions, cupric ions, organic acid, inorganic acid, and halide ions) to optimize performance. By adjusting these parameters, the etching process achieves the right balance of surface roughness and chemical reactivity, transforming the copper surface into a state that maximizes adhesion to polymeric materials while preventing delamination.
2Shape
If strong etching agents are used to roughen the metal surface, then surface roughness increases, but control over surface characteristics becomes difficult
Solution Approach 1:
The patent employs multiple controllable parameters (concentrations of five different chemical agents, temperature, treatment time) to precisely control the etching process. This multi-parameter approach allows fine-tuning of surface characteristics, achieving desired roughness levels while maintaining uniformity and predictability of surface properties across different batches.
Solution Approach 2:
The organic acid and inorganic acid components act as intermediaries that mediate between the strong oxidizing agents (ferric and cupric ions) and the copper surface. These intermediary substances control the etching rate and mechanism, ensuring that surface roughness develops in a controlled, uniform manner rather than through aggressive, unpredictable attack.
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 use of poly(ethyleneamino propionitrile) polymer in the composition significantly improves the adhesion of polymeric materials to metal surfaces, reducing delamination and providing better control over the surface characteristics, especially for copper and copper alloys.
Implementation Method 1
the strength of the adhesive bond formed between the copper metal of the circuitry innerlayers and the cured pre-preg layers... a layer of copper oxide, such as by chemical oxidation of the copper surfaces
Implementation Method 2
microetching composition... to produce a deep irregularly etched surface on the surface of copper or a copper alloy surface
Data Source
AI summary
A process is described for treating metal surfaces with roughening compositions that use poly(ethyleneamino propionitrile) polymer as an additive in the composition to improve adhesion of polymeric materials to the metal surfaces and to improve peel strength for thermal stability. The polymer of the invention may be added to compositions containing for example, cupric chloride and hydrochloric acid and is also usable in compositions containing an oxidizer/acid/azole mixture. Other additives, such as adiponitrile may also be beneficially added to compositions of the invention.