Poly(arylene ether) Adhesive for Nonpolar Dielectric Circuit Bonding
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Solution Overview
Problem
There is a need for circuit subassemblies with improved adhesion between conductive metal layers and dielectric substrates, especially at high temperatures, while maintaining electrical and mechanical properties, and for halogen-free flame retardant compositions that do not compromise physical properties like water absorption and thermal stability.
Innovation Solution
A circuit subassembly comprising a conductive layer, a dielectric layer made from a thermosetting composition with magnesium hydroxide and a nitrogen-containing compound, and an adhesive layer of poly(arylene ether) with optional polybutadiene or polyisoprene polymers and elastomeric block copolymers, achieving a UL-94 rating of at least V-1 without halogenated flame retardants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nonpolar resin systems (polybutadiene, polyisoprene, polyphenylene oxide) are used to achieve low dielectric constant and low dissipation factor, then electrical performance is improved, but adhesion to metallic surfaces is reduced
Solution Approach 1:
The patent introduces an adhesive layer as an intermediary between the nonpolar dielectric substrate and the conductive metal layer. This adhesive layer contains polar groups that provide strong adhesion to the metallic surface while being compatible with the nonpolar resin system, thus resolving the contradiction between electrical performance and adhesion strength
Solution Approach 2:
The patent creates a composite structure combining the nonpolar resin system with an adhesive layer containing polar groups. This composite approach allows the dielectric substrate to maintain low dielectric constant and dissipation factor while the adhesive layer provides the necessary adhesion to metallic surfaces
2Ease of manufacture
If dielectric substrates with low dielectric constants, low dissipation factors, and high glass transition temperatures are used to facilitate dense circuit layouts, then manufacturing capability is improved, but adhesion between conductive layer and dielectric substrate is reduced
Solution Approach 1:
The adhesive layer serves as a mediator between the high-performance dielectric substrate and the conductive layer. It is specifically formulated to adhere to both the nonpolar dielectric material and the metal surface, enabling dense circuit layouts while maintaining strong adhesion
Solution Approach 2:
The patent modifies the chemical composition parameters of the adhesive layer to optimize adhesion. By selecting specific polymers with appropriate polarity and molecular weight, the adhesive achieves strong bonding to both the dielectric substrate and conductive layer under the high glass transition temperature conditions
3Strength
If adhesion-promoting layers are used to improve bonding between dielectric substrate and conductive layer, then adhesion is improved, but surface softness increases leading to handling damage
Solution Approach 1:
The patent optimizes the molecular weight and crosslinking density parameters of the adhesive layer to achieve the right balance. By controlling these parameters, the adhesive provides strong adhesion while maintaining sufficient surface hardness to resist handling damage during processing
4Object-affected harmful factors
If halogenated flame retardants are used to achieve flame resistance, then flame retardancy is improved, but water absorption and electrical properties are compromised
Solution Approach 1:
The patent extracts and eliminates halogenated flame retardants from the dielectric substrate composition. Instead, it uses alternative flame retardant mechanisms that are compatible with nonpolar resin systems, thereby maintaining low water absorption and excellent electrical properties while achieving the required flame resistance
Solution Approach 2:
The patent changes the flame retardancy mechanism by using non-halogenated additives and modifying the resin composition parameters. This approach achieves UL-94 V-1 or better flame rating without the negative effects of halogenated compounds on electrical properties and water absorption
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 enhanced adhesion, flame resistance, and maintains low water absorption and electrical properties, with improved resistance to acids and solvents, and high temperature stability, while reducing the need for halogenated additives.
Implementation Method 1
adhesive layer disposed between and in intimate contact with the conductive layer and the dielectric layer
Implementation Method 2
thermosetting composition comprises, based on the total weight of the thermosetting composition: a polybutadiene or polyisoprene resin, about 30 to about 70 percent by weight of a magnesium hydroxide having less than about 1000 ppm of ionic contaminants, and about 5 to about 15 percent by weight of a nitrogen-containing compound
Implementation Method 3
dielectric layer formed from a thermosetting composition
Data Source
AI summary
A circuit subassembly, comprising: a conductive layer, a dielectric layer formed from a thermosetting composition, wherein the thermosetting composition comprises, based on the total weight of the thermosetting composition a polybutadiene or polyisoprene resin, about 30 to about 70 percent by weight of a magnesium hydroxide having less than about 1000 ppm of ionic contaminants, and about 5 to about 15 percent by weight of a nitrogen-containing compound, wherein the nitrogen-containing compound comprises at least about 15 weight percent of nitrogen; and an adhesive layer disposed between and in intimate contact with the conductive layer and the dielectric layer, wherein the adhesive comprises a poly(arylene ether), wherein the circuit subassembly has a UL-94 rating of at least V-1.