Photosensitive Polycyclic-Olefinic Polymer Films for Low-Loss Applications
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Solution Overview
Problem
Current insulating materials for electronic devices face challenges in achieving low dielectric constant, low-loss, and high thermal properties, particularly in maintaining low coefficient of thermal expansion (CTE) and high glass transition temperature (Tg) while being suitable for high-frequency applications and harsh conditions.
Innovation Solution
A composition comprising a polymer derived from substituted norbornene derivatives and a multifunctional diazirine that undergoes crosslinking to form a three-dimensional thermoset network, providing low dielectric constant and high thermal properties, along with the inclusion of a hydrogenated tackifier for copper-clad laminates and photoimageability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If films are made from addition polymerization of norbornene derivatives containing long side chains, then low dielectric constant and low-loss are achieved, but high coefficient of thermal expansion and low glass transition temperature occur
Solution Approach 1:
The patent combines norbornene derivative polymers (providing low dielectric constant and low-loss) with polar group-containing crosslinking agents (providing high glass transition temperature and low CTE) to create a composite crosslinked network that achieves all required properties simultaneously
Solution Approach 2:
The patent changes the chemical structure parameters of the crosslinking agents by introducing polar groups (ester, alcohol, carboxylic acid) to increase glass transition temperature and reduce CTE, while maintaining low dielectric properties through careful selection of non-polar norbornene backbone structures
2Temperature
If polar group substituted norbornenes are incorporated to generate low CTE and high Tg, then thermal properties improve, but dielectric constant and loss increase due to polarizability
Solution Approach 1:
The patent applies local quality by introducing polar groups only in the crosslinking agent molecules rather than in the main polymer chain, allowing localized thermal property enhancement without widespread increase in dielectric loss across the entire material
Solution Approach 2:
The patent uses non-polar norbornene derivative polymers as intermediaries that connect polar crosslinking agents, creating a bridge between polar groups (for thermal properties) and non-polar structures (for low dielectric loss), thereby mediating between conflicting requirements
3Strength
If conventional crosslinkers such as acrylates or maleimides are used to generate crosslinked networks, then crosslinking is achieved, but low-loss composition formation is prevented
Solution Approach 1:
The patent extracts and removes conventional crosslinkers (acrylates, maleimides) that cause high dielectric loss, replacing them with specially designed polar crosslinking agents based on norbornene derivatives that provide equivalent crosslinking strength without the harmful dielectric properties
Solution Approach 2:
The patent replaces expensive, complex conventional crosslinking systems with simpler, specially designed polar crosslinking agents that achieve the same crosslinking function more efficiently and with better 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 unprecedented low dielectric constant and low-loss properties, along with high thermal stability, enabling applications in high-frequency devices and harsh environments, such as millimeter-wave radar antennas, with improved adhesion and processing at elevated temperatures.
Implementation Method 1
a diazirine selected from the group consisting of: a bis-diazirine of formula (IIA), a tris-diazirine of formula (IIB), and a tetrakis-diazirine of formula (IIC) wherein: L is selected from the group consisting of —O—(C1-C16)alkylene-O—, —O—(CH2)2—O—(C6-C12)arylene-O—(CH2)2—O— and —O—(CH2)3—O—(C6-C12)arylene-O—(CH2)3—O—; A is a trivalent or tetravalent aliphatic, cycloaliphatic or aromatic moiety; Ar1, Ar2, Ar3 and Ara are the same or different and each independently selected from the group consisting of (C6-C12)arylene and (C6-C12) heteroarylene group optionally substituted with a group selected from (C1-C4)alkyl, (C1-C4)alkoxy, (C6-C10)aryl, (C6-C12)aryloxy, (C6-C12)aryl(C1-C4)alkyl and (C6-C12)aryl(C1-C4)alkyloxy; and R5, R6, R7 and R5 are the same or different and each independently selected from the group consisting of (C1-C6)alkyl, (C3-C7)cycloalkyl, (C6-C12)aryl, perfluoro (C1-C6)alkyl and perfluoro (C3-C7)cycloalkyl; wherein a film formed from the composition containing at least one of the diazirine of formula (IIA), (IIB) or (IIC) at an amount of at least about 2.5 parts per 100 parts of the polymer of formula (I) has a dielectric constant (Dk) less than 2.4 at a frequency of 10 GHz, a glass transition temperature greater than 210° C. and a coefficient of thermal expansion (CTE) less than 200 ppm/K
Data Source
AI summary
Embodiments in accordance with the present invention encompass compositions containing a polycycloolefinic polymer and at least one diazirine compound as described herein which when subjected to a suitable temperature or actinic radiation undergoes crosslinked network to form a three-dimensional insulating article which exhibits hitherto unattainable low dielectric constant and low-loss properties, and very high thermal properties. The compositions of this invention may additionally contain hydrogenated tackifiers, which provide much improved adhesive properties and are suitable in a number of opto-electronic applications including copper-clad laminates, among others. The compositions of this invention are also useful as insulating materials in millimeter wave radar antennas, among others.