DCPD-Modified Epoxy Resin for Low Dielectric PCB Laminates
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Solution Overview
Problem
Current resin systems for printed circuit boards, such as FR-4 substrates, fail to meet the requirements for high-frequency applications due to high dielectric constants, which lead to data loss and interference during transmission, and new resin systems deviate from existing manufacturing conditions, making them unsuitable for widespread use.
Innovation Solution
A resin varnish composition is developed using dicyclopentadiene (DCPD) with a saturated cyclic structure, reacting it with phenolic compounds and dihydrobenzoxazine or epoxy resins to create DCPD-PN, DCPD-PNE, and DCPD-BX resins, which are then mixed with flame retardants and curing agents to achieve low dielectric constants, low moisture absorption, and high thermal stability, compatible with existing manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If FR-4 resin system is used for printed circuit boards, then manufacturing compatibility is maintained, but dielectric constant remains too high (4.6) for high-frequency applications
Solution Approach 1:
The patent modifies the chemical structure of epoxy resin by introducing a saturated cyclic group (specifically a 7-membered ring structure formed by reaction of compound (1) with compound (2)). This structural parameter change reduces the dielectric constant from 4.6 (conventional FR-4) to below 4.2, while maintaining compatibility with existing manufacturing processes and curing agents.
Solution Approach 2:
The invention creates a composite resin system combining conventional epoxy resin with a newly synthesized resin containing saturated cyclic groups. This composite approach allows the new resin to contribute low dielectric properties while the epoxy base maintains manufacturing compatibility, achieving a balanced solution with dielectric constant below 4.2 and Tg above 140°C.
2Quantity of substance
If new resin systems (BT, cyanate ester, PTFE) are developed to reduce dielectric constant, then dielectric performance improves, but compatibility with existing manufacturing equipment and processes is lost
Solution Approach 1:
Instead of adopting entirely new resin systems like BT or cyanate ester, the patent introduces a specific structural modification to conventional epoxy resin - the saturated cyclic group formed by the reaction of compound (1) with compound (2). This targeted parameter change achieves dielectric constant reduction while preserving the fundamental epoxy chemistry that ensures manufacturing compatibility.
Solution Approach 2:
The newly synthesized resin with saturated cyclic groups acts as an intermediary component that bridges the gap between conventional epoxy resin and low-dielectric requirements. It modifies the dielectric properties of the system without requiring complete replacement of the epoxy base, thus maintaining compatibility with existing manufacturing processes while achieving the desired electrical performance.
3Quantity of substance
If resin with low dielectric constant is used for high-frequency transmission, then data transmission quality improves, but thermal stability and flame retardance must be maintained
Solution Approach 1:
The patent formulates a composite resin system where the low-dielectric saturated cyclic resin is combined with conventional epoxy resin and compatible curing agents. This composite structure achieves dielectric constant below 4.2 while maintaining Tg above 140°C and passing UL94 V-0 flame retardance tests, as the epoxy base provides thermal stability and the new resin provides low dielectric properties.
Solution Approach 2:
The invention carefully controls the molecular structure parameters of the synthesized resin, specifically the saturated cyclic group formation, to optimize the balance between dielectric constant and thermal properties. The structural design ensures that while dielectric constant is reduced, the thermal glass transition temperature remains above 140°C, meeting both electrical and thermal requirements.
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 resulting resin varnish composition enables the production of copper clad laminates with dielectric constants between 3.89 and 4.32 and dissipation factors between 0.008 and 0.016, meeting UL94 V-0 flame retardant standards and providing superior thermal stability and chemical resistance.
Implementation Method 1
dicyclopentadiene (DCPD) with a saturated cyclic structure, reacting it with phenolic compounds and dihydrobenzoxazine or epoxy resins to synthesize a phenolic resin (dicyclopentadiene-phenolic Novolac, DCPD-PN) containing a DCPD structure
Implementation Method 2
low moisture absorption
Data Source
AI summary
This invention relates to a low dielectric resin varnish composition for laminated printed circuit boards, wherein the resin composition includes (A) Dicyclopentadiene-Phenolic Novolac resin (abbreviated as DCPD-PN); or (B) at least one kind of dicyclopentadiene Phenolic Novolac Epoxy resins(DCPD-PNE, referred to as Resin 1); or (C) a novel Dicyclopentadiene- Dihydrobenzoxazine resin (DCPD-BX, referred to as Resin 2); or the mixture of (B) and (C), and (D) Flame retardant agent, curing agent and accelerating agent solutions. Because all of component (A) DCPD-PN, component (B) DCPD-PNE and component (C) DCPD-BX in this resin varnish composition contain a saturated multi-cyclic structure of dicyclopentadiene, the resin varnish shows lower dipole, dielectric constant (Dk), dissipation factor (Df) and moisture absorption; and via adding a brominated or phosphorus flame retardant, the composition exhibits high thermal stability characteristic. The copper clad laminates obtained in accordance with the invention meet not only the demand of low dielectric constant (Dk <4.0 @ 1 GHz) and low dissipation factor (Df <0.009 @ 1GNz), but also possesses high heat stability and low moisture absorption characteristics, thus are widely applied to high-performance electronic materials.