Cyclic Olefin Copolymer Insulating Body for High-Frequency Wiring Boards
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Solution Overview
Problem
Cyclic olefin copolymers used in electronic components have limitations in dielectric properties and thermal stability, particularly when heated above their glass transition temperature, leading to reduced bond strength with copper foils and limited high-frequency applications.
Innovation Solution
Incorporating a peroxide with a benzene ring into the cyclic olefin copolymer resin composition to enhance crosslinking, resulting in an organic insulating body with improved thermal stability and reduced dielectric tangent, while maintaining low dielectric constant and surface roughness for better copper foil bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cyclic olefin copolymer is used as insulating material, then ease of manufacture and low dielectric constant are achieved, but dielectric tangent is not sufficiently low and thermal stability deteriorates above glass transition temperature
Solution Approach 1:
The patent creates a composite material system by combining cyclic olefin copolymer with specific additives including peroxides (2,5-dimethyl-2,5-di(t-butylperoxide) and/or 2,4,6-tri(t-butylperoxy)-s-trimethylsultone), silane coupling agents, and flame retardants. This composite approach allows the material to achieve both ease of manufacture and improved thermal stability, resolving the contradiction between processing convenience and high-temperature reliability.
Solution Approach 2:
The patent modifies the chemical and physical parameters of the cyclic olefin copolymer by controlling the glass transition temperature to be 105°C or higher and the melting point to be 140°C or higher. Specific compositional parameters are established: peroxide content of 0.1-5 parts by mass, silane coupling agent of 0.1-5 parts by mass, and flame retardant of 10-40 parts by mass. These parameter changes enable the material to maintain dimensional stability and low dielectric tangent at elevated temperatures while remaining manufacturable.
2Temperature
If crosslinking agent or flame retardant is added to cyclic olefin copolymer, then glass transition temperature is increased, but dielectric tangent is also increased
Solution Approach 1:
The patent introduces silane coupling agents as intermediary substances that mediate between the crosslinking/flame retardant functions and the dielectric properties. The silane coupling agent (0.1-5 parts by mass) acts as a bridge that enables crosslinking and flame retardancy while maintaining low dielectric tangent through its specific chemical structure and bonding characteristics, preventing the direct negative correlation between Tg enhancement and dielectric performance.
Solution Approach 2:
The patent precisely controls the dosage parameters of additives to optimize the balance between Tg enhancement and dielectric tangent suppression. The peroxide content is limited to 0.1-5 parts by mass, silane coupling agent to 0.1-5 parts by mass, and flame retardant to 10-40 parts by mass. These controlled parameter changes ensure that the glass transition temperature reaches 105°C or higher while the dielectric tangent remains at 0.004 or lower at 10 GHz and 25°C.
3Reliability
If copper foil surface roughness is reduced for high frequency applications, then dielectric properties are improved, but bond strength between copper foil and organic insulating body is reduced
Solution Approach 1:
The silane coupling agent serves as a chemical intermediary between the copper foil surface and the organic insulating body. It forms strong chemical bonds with both the metal surface and the polymer matrix, creating an intermediate bonding layer that maintains strong adhesion even when the copper foil surface roughness is minimized for high-frequency performance. This intermediary mechanism decouples the trade-off between dielectric properties and bond strength.
Solution Approach 2:
The patent creates a composite bonding system consisting of copper foil, silane coupling agent layer, and cyclic olefin copolymer insulating body. This multi-layer composite structure allows the copper foil to have smooth surface for high-frequency applications while the silane coupling agent provides strong chemical bonding, and the polymer provides mechanical support and dielectric properties. The composite approach resolves the contradiction between surface smoothness and bond strength.
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 low dielectric constant and tangent values at high temperatures, enhancing heat resistance and high-frequency performance, and improves bond strength between the copper foil and organic insulating body.
Implementation Method 1
Incorporating a peroxide with a benzene ring into the cyclic olefin copolymer resin composition to enhance crosslinking
Implementation Method 2
achieves low dielectric constant and tangent values at high temperatures, enhancing heat resistance
Data Source
AI summary
There is provided an organic insulating body which contains a cyclic olefin copolymer as a main component and a peroxide having a benzene ring, and has such a property that a loss tangent peak appears at 120° C. or higher in a dynamic mechanical analysis.