Composite Woven Fabric for Low Dielectric PCBs
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Solution Overview
Problem
High-frequency printed wiring boards face challenges with high dielectric constants and loss tangents, poor drilling properties, and high costs due to the use of materials like D glass and quartz glass fibers, and require a base material with low linear expansion coefficients suitable for advanced multilayer boards.
Innovation Solution
A composite woven fabric combining quartz glass fibers and polyolefin fibers, with a ratio of quartz glass fibers between 10 vol.% and 90 vol.%, is used to achieve a low dielectric constant, low dielectric loss tangent, and low linear expansion coefficient, improving drilling properties and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quartz glass fiber is used as base material, then dielectric constant and dielectric loss tangent are minimized, but drilling property deteriorates due to excessive hardness
Solution Approach 1:
The patent uses a composite woven fabric combining quartz glass fibers (10-90 vol%) with polyolefin fibers (10-90 vol%). The quartz glass fibers provide excellent dielectric characteristics (low dielectric constant and low dielectric loss tangent), while the polyolefin fibers soften the overall structure, improving drilling properties and reducing the excessive hardness issue of pure quartz glass fiber boards.
2Reliability
If D glass fiber is used, then dielectric constant and dielectric loss tangent are improved, but productivity deteriorates due to high melting temperature
Solution Approach 1:
The patent replaces D glass fiber with a composite of quartz glass fibers and polyolefin fibers. This combination maintains excellent dielectric characteristics while improving productivity, as the polyolefin component has lower melting temperature and better processability compared to D glass fiber's high melting temperature.
3Reliability
If fluorine-based resin is used, then dielectric characteristic is excellent, but layer capacity is limited due to difficulty in multilayer construction
Solution Approach 1:
The patent uses a composite woven fabric of quartz glass fibers and polyolefin fibers that can be effectively used in multilayer constructions. The composite structure provides excellent dielectric characteristics while enabling advanced multilayer board designs, overcoming the limitation of fluorine-based resin boards that are difficult to turn into multiple layers.
4Reliability
If quartz glass fiber is used, then linear expansion coefficient is minimized, but cost increases due to expensive processing requirements
Solution Approach 1:
The patent combines quartz glass fibers (providing low linear expansion coefficient) with polyolefin fibers (providing cost-effectiveness and easier processing). This composite approach maintains the low linear expansion coefficient required for high-frequency applications while reducing the overall cost compared to using pure quartz glass fiber boards.
Data Source
AI summary
Disclosed is a printed wiring board which attains aims of printed wiring boards required for realizing high-speed, high-frequency semiconductor devices, namely a printed wiring board having low dielectric constant, low dielectric loss tangent and low linear expansion coefficient. Also disclosed is a composite woven fabric suitably used as a base material for such a printed wiring board. Specifically disclosed is a composite woven fabric containing quartz glass fibers and polyolefin fibers, in which the ratio of the quartz glass fibers to the composite woven fabric is set at 10 vol % or more and 90 vol % or less. It is preferred that the quartz glass fibers each have a filament diameter of 3 μm or more and 16 μm or less, and the composite woven fabric has a thickness of 200 μm or less.