Microetching Agent for Uniform Copper Foil Roughening
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Solution Overview
Problem
Conventional microetching agents struggle to form a uniform roughened shape on both rolled copper and electrolytic copper foils due to differences in crystallinity, leading to uneven adhesion and process complexity.
Innovation Solution
An acidic aqueous microetching agent containing a cupric ion source, halide ion source, sulfate ion source, and a water-soluble polymer with an amino or quaternary ammonium group is used to create a uniform roughened shape, independent of copper foil type, by maintaining specific molar concentrations and pH levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional microetching agents are used on rolled copper foil, then the etching process can be performed, but uniform roughening is difficult to achieve due to large crystal grains and high crystal plane orientation uniformity
Solution Approach 1:
The patent changes the chemical parameters of the microetching agent by specifying precise molar concentration ratios between cupric ion source (0.01-1.0 mol/L) and halide ion source (0.01-1.0 mol/L), along with pH control (2-4) and temperature control (20-40°C). These parameter changes enable uniform etching of rolled copper foil by optimizing the etching reaction conditions to overcome the uniform crystal structure of rolled copper.
Solution Approach 2:
The patent uses a composite etching system combining multiple components: cupric ion source (e.g., CuSO4), halide ion source (e.g., HCl), sulfate ion source, and water-soluble polymer. This composite chemical system works synergistically to achieve uniform roughening on rolled copper, where each component contributes to controlling the etching rate and uniformity across the copper surface.
2Manufacturing precision
If different types of microetching agents are used for different copper foil types, then appropriate roughening can be achieved for each type, but process management becomes complicated
Solution Approach 1:
The patent creates a universal microetching agent formulation that can effectively roughen both rolled copper foil and electrolytic copper foil with the same chemical composition and processing conditions. The standardized formulation (specific molar concentrations of cupric ions, halide ions, pH 2-4, temperature 20-40°C) serves multiple functions for different copper types, eliminating the need for separate etching processes.
Solution Approach 2:
The patent applies homogeneity by using the same microetching agent composition and processing parameters for both rolled copper and electrolytic copper foils. This standardized approach ensures consistent roughening quality across different copper types without requiring process differentiation, thereby simplifying process management while maintaining manufacturing precision.
3Manufacturing precision
If conventional microetching agents are used on electrolytic copper foil, then uniform roughening can be achieved, but the same agent does not work well on rolled copper foil
Solution Approach 1:
The patent develops a universal etching formulation that maintains effectiveness across different copper foil types. The standardized composition (cupric ion source 0.01-1.0 mol/L, halide ion source 0.01-1.0 mol/L, pH 2-4, temperature 20-40°C) provides adaptability to both electrolytic copper with fine crystal grains and rolled copper with large crystal grains, achieving uniform roughening on both substrates.
Solution Approach 2:
The patent optimizes etching parameters including pH (2-4), temperature (20-40°C), and ion concentrations to create conditions that are universally effective for different copper types. These parameter changes ensure the etching reaction proceeds uniformly regardless of the copper foil's crystal structure, enhancing both manufacturing precision and adaptability.
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 achieves uniform adhesion to resin on both rolled and electrolytic copper foils, eliminating the need for different etching agents based on copper type, thereby simplifying the process and ensuring consistent surface roughening.
Implementation Method 1
an acidic aqueous solution containing an inorganic acid, a cupric ion source... When a microetching agent is brought into contact with a metal surface, irregularities are formed to roughen the surface
Implementation Method 2
a halide ion source... difference in the etching rate by the crystal orientation of the crystal grains of the metal
Implementation Method 3
a water-soluble polymer having a weight-average molecular weight of 1000 or more and having an amino group or a quaternary ammonium group in the side chain
Data Source
AI summary
Disclosed are: a microetching agent which can form roughened shapes less affected by differences in the crystallinity of the copper and with which roughened shape excellent in terms of adhesiveness to resins, etc. can be formed on either electrolytic copper or rolled copper; and a method for producing a wiring board which includes a step of roughening a copper surface using the microetching agent. In the present invention, the microetching agent for copper is an acidic aqueous solution containing an inorganic acid, a cupric ion source, a halide ion source, and a polymer. The polymer has a functional group containing a nitrogen atom. It is preferable that the microetching agent contain a sulfate ion source.