Copper Foil Electroplating with Tungstate for High Peeling Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional copper foils for printed circuit boards face challenges in achieving sufficient peeling strength, heat resistance, acid resistance, and environmental sustainability, particularly when used with high glass transition temperature (Tg) epoxy substrates, due to surface roughening methods that can lead to copper powder dropping and poor etching characteristics.
Innovation Solution
A copper foil manufacturing method involving a specific electrolyte solution and electrolysis treatment, where the copper foil is washed with copper sulfate and sulfuric acid, followed by electroplating with a sodium phosphotungstate solution to uniformly deposit copper, and subsequent layers of heat-resistant zinc alloy, alkali chromium, and silane coupling agents are applied to enhance adhesion and resistance without causing powder dropping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If surface roughening treatment is conducted to enhance peeling strength between copper foil and high Tg substrate, then peeling strength is improved, but copper powder dropping and abnormal etching residues occur
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte solution by replacing toxic elements (arsenic, antimony, bismuth, selenium) with non-toxic alternatives (sodium phosphotungstate, sodium metatungstate, sodium polytungstate). This parameter substitution maintains the roughening effect and peeling strength while eliminating copper powder dropping and environmental harm.
Solution Approach 2:
The patent uses disposable, non-toxic tungstate-based electrolyte components that can be easily replaced or disposed of without environmental contamination, replacing the persistent toxic elements that cause powder dropping and etching problems.
2Strength
If surface roughening treatment is conducted to enhance peeling strength, then adhesion to substrate is improved, but etching characteristics deteriorate
Solution Approach 1:
The patent modifies the electrolyte composition parameters by eliminating toxic elements that cause excessive roughening and poor etching. The controlled use of tungstate ions provides sufficient roughening for adhesion while maintaining a surface morphology that accepts etching solutions uniformly, preventing deckle edge phenomena.
3Manufacturing precision
If low roughness copper foil is used for high density and fine circuit lines, then manufacturing precision is improved, but lamination peeling strength deteriorates
Solution Approach 1:
The patent applies local quality enhancement by creating a controlled rough surface layer through electrochemical roughening with tungstate electrolyte. This localized surface modification provides anchoring points for resin adhesion without affecting the overall flatness and precision required for high-density circuit fabrication.
Solution Approach 2:
The patent creates a composite surface structure through electrochemical deposition, forming a multi-layered surface morphology with peaks and valleys that combines the benefits of roughness (for adhesion) and controlled geometry (for precision). The resulting surface acts as a composite interface between the copper foil and resin substrate.
4Strength
If toxic elements (arsenic, antimony, bismuth, selenium) are added to electrolyte solution for effective copper roughening, then peeling strength is improved, but environmental protection is compromised
Solution Approach 1:
The patent extracts and removes toxic elements (arsenic, antimony, bismuth, selenium) from the electrolyte solution composition. By eliminating these harmful substances while retaining the essential roughening function through tungstate-based alternatives, the process achieves both effective adhesion and environmental protection.
Solution Approach 2:
The patent converts the harmful effect of toxic elements into a beneficial non-toxic process by using tungstate ions that provide the same roughening and adhesion-enhancing effects without environmental pollution. The previously harmful chemical composition is transformed into an environmentally friendly alternative.
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 results in copper foils with improved peeling strength, heat resistance, acid resistance, and reduced powder dropping, suitable for various printed circuit boards, while avoiding environmental issues associated with toxic elements and ensuring efficient etching characteristics.
Implementation Method 1
the adhesion surface of copper foil is washed with copper sulfate and sulfuric acid solution
Implementation Method 2
electroplating with a sodium phosphotungstate solution to uniformly deposit copper
Implementation Method 3
electrolysis treatment, where the copper foil is washed with copper sulfate and sulfuric acid, followed by electroplating
Implementation Method 4
subsequent layers of heat-resistant zinc alloy, alkali chromium, and silane coupling agents are applied to enhance adhesion and resistance
Data Source
AI summary
The present invention relates to a manufacturing method for a fine grain surface copper foil with the low roughness, high peeling strength, high chemical resistance, high heat resistance, high resistance to moisture absorption and good etching properties, and applicable to all kinds of printed circuit boards. The technical characteristics are that the adhesion surface of copper foil is electroplated in an electroplating bath composed of copper sulfate, sulfuric acid, tungsten compounds to obtain a roughening treatment layer which is then treated with a electroplating copper foil method for anti-rust and thermoresistance known to the art to get a Zn alloy thermoresistant layer.