Multilayer Insulating Structure for Smooth Copper Foil Adhesion
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Solution Overview
Problem
Conventional insulating materials struggle to provide high adhesion to the smooth surface of copper foil, which is essential for high-frequency applications such as multilayer substrates and transmission lines, due to their inherent properties and processing challenges.
Innovation Solution
A multilayer structure comprising an insulating layer made of an olefin-aromatic vinyl compound-aromatic polyene copolymer with a surface modifier, specifically bonded to the smooth surface of copper foil, while the resin layer is bonded to the roughened surface, ensuring high adhesive strength and low dielectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fluorine-based resins such as perfluoroethylene are used, then low dielectric constant and low dielectric loss are achieved, but adhesion to copper foil and film formability deteriorate
Solution Approach 1:
The patent uses a composite material system combining fluorinated polymer (for low dielectric properties) with silane coupling agent (for adhesion promotion). The silane-modified fluorinated polymer creates a composite that maintains the low dielectric constant and loss of the fluorinated base while adding adhesion capability through the silane component that bonds to copper foil surface.
Solution Approach 2:
The patent modifies the chemical parameters of the fluorinated resin by introducing silane functional groups. This parameter change transforms the inert fluorinated polymer into a material with surface-reactive properties, enabling adhesion to copper foil while preserving the bulk dielectric properties.
2Ease of operation
If conventional resins such as epoxy or polyimide are used, then ease of handling and heat resistance are achieved, but dielectric constant and dielectric loss increase
Solution Approach 1:
The patent fundamentally changes the chemical composition parameter from conventional epoxy/polyimide resins to fluorinated polymers with silane modification. This parameter change achieves simultaneously low dielectric loss (inherent property of fluorinated structures) and adequate adhesion (through silane functionality), while maintaining processability similar to conventional resins.
3Reliability
If hydrocarbon-based resins with functional groups are used, then curability is achieved, but dielectric properties deteriorate due to polarity
Solution Approach 1:
The patent applies local quality by concentrating the polar functional groups (silane) only at the surface/interface region where adhesion is needed, while the bulk of the material remains non-polar fluorinated polymer. This spatial separation allows curability and adhesion at the interface without compromising the low dielectric loss of the bulk material.
Solution Approach 2:
The silane coupling agent acts as an intermediary substance between the non-polar fluorinated polymer and the copper foil surface. It provides the polar functional groups needed for curability and adhesion, while the fluorinated polymer backbone maintains the low dielectric properties.
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 high adhesive strength to the smooth surface of copper foil, providing a low dielectric constant and dielectric loss tangent, suitable for high-frequency applications like transmission lines and antennas, with improved physical properties and heat resistance.
Implementation Method 1
the insulating layer contains an olefin-aromatic vinyl compound-aromatic polyene copolymer and a surface modifier
Data Source
AI summary
A multilayer structure includes at least one insulating layer(s), at least one resin layer(s), and at least one copper foil(s) each having a smooth surface and a roughened surface, wherein the insulating layer contains an olefin-aromatic vinyl compound-aromatic polyene copolymer and a surface modifier, wherein the resin layer contains one or more selected from the group consisting of polyimide, liquid crystal polymer, polyphenylene ether, polyfunctional aromatic vinyl resin, epoxy resin, and the same composition as in the insulating layer, wherein at least one surface of the respective insulating layer(s) is bonded to a smooth surface of the copper foil, and wherein, for each respective resin layer: at least one surface of the resin layer is bonded to the roughened surface, and the resin layer is not bonded to the smooth surface; or both surfaces of the resin layer are not bonded to the copper foil.