Composite Material for High-Frequency Circuit Substrates
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Solution Overview
Problem
Conventional high-frequency circuit substrates face challenges with high dielectric loss, conductor loss, and radiation loss due to materials with high dielectric constants and loss tangents, which affect signal reliability and heat resistance, and existing solutions like polytetrafluoroethylene are difficult to process and have poor heat resistance.
Innovation Solution
A composite material comprising a thermosetting mixture with a resin containing high vinyl content and a solid styryl resin with unsaturated double bonds, combined with fiberglass cloth and a cure initiator, is used to create a high-frequency circuit substrate with improved dielectric properties, heat resistance, and processing ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If polytetrafluoroethylene is used as substrate material, then dielectric loss is reduced, but processability deteriorates
Solution Approach 1:
The patent uses a composite material system consisting of polybutadiene resin (providing low dielectric loss), silica filler (improving processability and reducing tackiness), and fiberglass cloth (providing mechanical strength). This composite approach allows the material to achieve both low dielectric loss and good processability, resolving the contradiction between these two properties.
2Strength
If high molecular weight polybutadiene styrene copolymer is used to improve tacky property, then adhesion is improved, but processing property deteriorates
Solution Approach 1:
The patent carefully controls the molecular weight parameter of the polybutadiene styrene copolymer to be less than 5000, and adjusts the proportion of rigid structure benzene ring in the resin molecule to be not less than 20%. These parameter changes enable the resin to achieve adequate tacky property while maintaining good processing property, resolving the contradiction between adhesion and processability.
3Strength
If silica filler is added to improve tacky property, then adhesion is improved, but drill bit wear increases
Solution Approach 1:
The patent controls the proportion of silica filler within 10-50 parts by weight per 100 parts of resin composition, and ensures the proportion of rigid structure benzene ring is not less than 20%. This balanced composition provides adequate tacky property while limiting excessive silica content that would cause severe drill bit wear, thus resolving the contradiction between adhesion improvement and tool wear reduction.
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 composite material achieves low dielectric constant, low dielectric loss tangent, and high heat resistance, enabling efficient processing and reliable high-frequency performance while reducing the tacky issues of liquid resin prepregs.
Implementation Method 1
a solid styryl resin of middle or low molecular weight with unsaturated double bonds... a resin containing high vinyl content... cross-linked segments
Implementation Method 2
use fiberglass cloth as reinforcing material to make circuit substrate which has excellent dielectric properties
Data Source
AI summary
The present invention relates to a composite material, a high-frequency circuit substrate made therefrom and making method thereof. The composite material comprises 20-70 parts by weight of thermosetting mixture, a fiberglass cloth, a powder filler, a flame retardant, and a cure initiator. The thermosetting mixture includes a resin containing vinyl in the amount of more than 60% composed of carbon and hydrogen with its molecular weight being less than 11000, and a solid styryl resin of middle or low molecular weight with unsaturated double bonds. The made high-frequency circuit substrate comprises a plurality of prepregs mutually overlapped, and copper foils respectively covered on both sides of overlapped prepregs. Each prepreg is made from the composite material. The composite material of the present invention enable to readily make prepregs. The high-frequency circuit substrate made from the composite material has low dielectric constant, low dielectric loss tangent, and good heat resistance, and is convenient for process operation. Therefore, the composite material of the present invention is suitable for making circuit substrates of high-frequency electronic equipments.