Fluorinated Polyimide Resin for Low Dielectric Loss PCBs
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Solution Overview
Problem
Conventional polyimide resin-based printed circuit boards exhibit high moisture absorption and poor adhesion between the copper foil and circuit substrate, leading to increased dielectric loss and reliability issues in humid environments, while liquid-crystal polymer-based boards suffer from poor adhesion and peeling of the copper foil.
Innovation Solution
A resin composition comprising a specific compound with a defined structure, combined with an anhydride, is used to form a polyimide or polyurethane-polyimide layer that exhibits low dielectric properties and high adhesive strength, thermal tolerance, and chemical resistance, applied to a metal foil substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional polyimide resin is used, then thermal stability is excellent, but moisture absorption is high and dielectric loss factor increases in humid atmosphere
Solution Approach 1:
The patent modifies the polyimide resin by introducing fluorinated groups at specific positions in the molecular structure. This local chemical modification creates regions with low polarity and high hydrophobicity, which locally resist moisture absorption while maintaining the overall thermal stability of the polyimide backbone structure.
Solution Approach 2:
The invention creates a composite resin system by combining fluorinated polyimide components with specific structural units (including cyclic carbonate groups). This composite approach integrates the thermal stability of polyimide with the moisture resistance of fluorinated structures, achieving both properties simultaneously in the cured resin system.
2Loss of energy
If copper foil surface roughness is reduced, then transmission loss of high-frequency signal is reduced, but bonding strength between copper foil and circuit substrate is reduced
Solution Approach 1:
The patent changes the chemical parameters of the resin system by introducing fluorinated groups and cyclic carbonate structures. These parameter changes create a cured resin with optimized surface properties that enhance adhesion to smooth copper foil surfaces, allowing signal transmission loss reduction through surface roughness control without sacrificing bonding strength.
Solution Approach 2:
The fluorinated resin composition creates a localized interfacial layer with enhanced adhesive properties between the circuit substrate and copper foil. This local quality enhancement at the interface allows the bulk copper foil to maintain smooth surfaces for low signal loss while the interfacial region provides strong bonding through the specialized resin chemistry.
3Reliability
If liquid-crystal polymer is used, then dielectric coefficient and dielectric loss factor are low, but adhesion between layer and copper foil is poor
Solution Approach 1:
The invention creates a composite resin system that integrates the low dielectric properties of liquid-crystal polymer structures with the adhesion-enhancing fluorinated groups and cyclic carbonate units. This composite material approach combines the beneficial dielectric characteristics with improved interfacial adhesion, resolving the contradiction between low dielectric loss and strong bonding to copper foil.
Solution Approach 2:
The fluorinated cyclic carbonate-containing resin creates a localized adhesion-promoting interface between the low-dielectric liquid-crystal polymer layer and the copper foil substrate. This local quality differentiation allows the bulk material to maintain low dielectric properties while the interfacial region provides strong bonding through enhanced chemical interactions.
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 provides a cured product with stable dielectric characteristics, low dielectric loss, and improved adhesion to the metal foil substrate, maintaining performance even after water absorption, thus enhancing the reliability and durability of high-frequency circuit boards.
Implementation Method 1
a layer including a cured product of the resin composition is disposed on the surface of the conductive layer
Implementation Method 2
the resin composition includes the compound and an anhydride
Data Source
AI summary
A compound, a resin composition and a laminated substrate thereof are provided. The compound has a structure represented by Formula (I)wherein A1 is C24-48 alkylene group, C24-48 alkenylene group, C24-48 alkynylene group, C24-48 alicyclic alkylene group, C24-48 alicyclic alkenylene group, or C24-48 alicyclic alkynylene group. A2 is C2-12 alkylene group, C6-C25 arylene group with two reactive groups, C4-8 cycloalkylene group, C5-25 heteroarylene group, divalent C7-C25 alkylaryl group, divalent C7-25 acylaryl group, divalent C6-25 aryl ether group, or divalent C7-25 acyloxyaryl group; and, n≥1.