Copper-Clad Laminate Film With Metal-Oxide Tie Layer for Low-Loss Adhesion
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Solution Overview
Problem
Existing copper-clad laminate films face challenges in achieving low thermal expansion, low permittivity, low dielectric loss, and low transmission loss while maintaining superior etching resistance and chemical resistance, especially in high-frequency applications and acidic/alkaline environments, which are critical for miniaturized electronic devices.
Innovation Solution
A copper-clad laminate film comprising a polyimide-based substrate with a fluorine layer, a tie-layer with specific metal elements (Group 4, 6, 13, 14) having a metal-oxygen bond dissociation energy of 400 kJ/mol, and a copper layer, which enhances adhesion and reduces transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional copper-clad laminate films are used, then basic structural integrity is maintained, but thermal expansion is high, permittivity is high, dielectric loss is high, and transmission loss is high at high frequencies
Solution Approach 1:
The patent employs a composite substrate structure combining polyimide base material with fluorinated surface layers and metal oxide tie-layers. This composite approach allows the bulk polyimide to provide low thermal expansion (25 ppm/°C or less) while the fluorinated surface and metal oxide layers (TiO2, SiO2, Al2O3) provide chemical inertness and etching resistance. The multi-layer composite resolves the contradiction by assigning different functional properties to different layers.
Solution Approach 2:
The patent modifies the surface chemistry parameters of the polyimide substrate by introducing fluorinated groups and metal oxide layers. The fluorination reduces surface energy and improves chemical resistance, while the metal oxide layers with specific bond dissociation energies (400-800 kJ/mol) provide etching resistance. These parameter changes in surface composition and chemistry enable simultaneous achievement of low thermal expansion and high etching resistance.
2Reliability
If conventional copper-clad laminate films are used, then basic electrical conductivity is maintained, but permittivity is high and dielectric loss is high at high frequencies
Solution Approach 1:
The patent uses a composite substrate system where the polyimide base provides mechanical support and the fluorinated surface layers with specific metal oxide coatings provide optimized dielectric properties. The fluorinated polyimide structure inherently provides low permittivity (Dk ≤ 3.5) and low dielectric loss (Df ≤ 0.005) at high frequencies, eliminating the need for additional complex dielectric layers while maintaining electrical performance.
3Strength
If conventional copper-clad laminate films are used, then copper adhesion is achieved, but adhesion strength is insufficient in harsh chemical environments
Solution Approach 1:
The patent introduces metal oxide tie-layers (TiO2, SiO2, Al2O3, ZrO2, HfO2) as intermediary layers between the fluorinated polyimide substrate and the copper foil. These tie-layers serve dual functions: they chemically bond to both the substrate and copper, providing strong adhesion, and they form chemically inert barriers that protect the copper-substrate interface from harsh chemical environments. The high bond dissociation energy (400-800 kJ/mol) of these metal oxides ensures stable bonding under chemical stress.
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 film achieves low thermal expansion, low permittivity, and low dielectric loss with superior etching and chemical resistance, suitable for high-frequency applications and harsh environments, supporting the development of miniaturized electronic devices.
Implementation Method 1
the at least one metal element has a metal-oxygen (M-O) bond dissociation energy of 400 kJ/mol or more
Data Source
AI summary
Disclosed are a copper-clad laminate film and an electronic device including the same. The copper-clad laminate film includes: a polyimide-based substrate having a fluorine layer disposed on at least one side thereof; a tie-layer disposed on the polyimide-based substrate having the fluorine layer placed thereon; and a copper layer disposed on the tie layer, wherein the tie-layer includes at least one metal element selected from among metal elements of Group 4, Group 6, Group 13, and Group 14 in the Periodic Table, and the at least one metal element may have a metal-oxygen (M-O) bond dissociation energy of 400 kJ/mol or more.