Dielectric Composite for High-Frequency PCBs
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Solution Overview
Problem
Existing dielectric composites for printed circuit boards face challenges in achieving high dielectric constant (Dk) and low thermal coefficient of dielectric constant (TCDk) while maintaining good adhesiveness to metal foils, especially under high-frequency and high-temperature conditions, and are prone to defects such as voids and poor appearance due to high filler content and poor processability.
Innovation Solution
A dielectric composite is formed by combining at least two dielectric layers with different TCDk values, using thermal-curable resins and inorganic fillers, to achieve a Dk not lower than 4 and a TCDk ranging from 0 to −150 ppm/°C, with excellent adhesiveness and thermal resistance, suitable for high-frequency transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large amount of filler is added to increase dielectric constant, then the Dk value increases, but the viscosity of the varnish becomes too high to be processed
Solution Approach 1:
The patent changes the particle size parameter of the filler by using nanosized inorganic powders (1-100 nm) instead of conventional larger particles. This parameter change allows achieving high Dk values with lower filler content, thereby maintaining acceptable viscosity and processability. The nanoscale dimensions provide high surface area to volume ratio, enhancing dielectric constant while improving varnish flow characteristics.
Solution Approach 2:
The patent employs composite materials by combining organic resin matrix with nanosized inorganic fillers. This composite approach creates a synergistic effect where the nanofillers provide high dielectric constant contribution without the excessive viscosity problems associated with conventional filler loads. The composite structure allows optimal balance between Dk enhancement and manufacturability.
2Quantity of substance
If excessive fillers are used to achieve desired dielectric properties, then Dk increases, but defects such as voids and bad appearance are generated
Solution Approach 1:
The patent applies parameter change by reducing filler particle size to nanoscale (1-100 nm), which fundamentally alters the filling behavior. Nanosized particles pack more efficiently and uniformly throughout the resin matrix, eliminating the aggregation and void formation problems that occur with excessive conventional-sized fillers. This enables achieving target Dk values with appropriate filler loading without generating defects.
Solution Approach 2:
The patent uses nanosized inorganic powders that, while small, provide disproportionate dielectric enhancement per unit weight. This allows achieving high Dk with moderate filler content, avoiding the need for excessive filler loading that would cause voids and appearance defects. The high surface area to volume ratio of nanoparticles maximizes the dielectric contribution at lower concentrations.
3Quantity of substance
If high filler content is used to increase dielectric constant, then Dk increases, but adhesion between dielectric layer and metal foil becomes unsatisfactory
Solution Approach 1:
The patent changes the filler particle size parameter to nanoscale dimensions, which fundamentally improves adhesion characteristics. The small particle size allows for more uniform distribution and better interfacial bonding between the dielectric layer and metal foil. Nanosized fillers create a finer microstructure that enhances mechanical interlocking and chemical bonding, thereby improving adhesion strength compared to conventional filler sizes.
Solution Approach 2:
The patent employs a composite material system where nanosized inorganic fillers are dispersed in an organic resin matrix. This composite structure provides both the desired dielectric constant and improved adhesion properties. The organic resin component ensures good bonding to metal foils, while the nanofillers provide dielectric enhancement without compromising the adhesive interface.
4Reliability
If conventional ceramic fillers are used to achieve high Dk and low TCDk, then dielectric properties improve, but cost increases making it unfavorable for mass production
Solution Approach 1:
The patent substitutes expensive conventional ceramic fillers with nanosized inorganic powders that are more cost-effective for mass production. The nanosized fillers provide comparable or superior dielectric properties at lower material costs and with improved processing characteristics. This substitution maintains high Dk and low TCDk performance while reducing overall production costs, making the technology economically viable for mass manufacturing.
Solution Approach 2:
The patent applies parameter change by using nanosized inorganic powders with specific surface area and particle size characteristics that optimize both dielectric performance and cost-effectiveness. The nanoscale dimensions enable achieving target dielectric properties with lower filler loading, reducing material costs and improving processability, thereby making mass production more economically attractive compared to conventional ceramic filler approaches.
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 provides improved thermal resistance, adhesiveness, and desired dielectric properties, enhancing the performance of printed circuit boards for high-frequency applications with stable signal transmission under varying temperatures and maintaining good appearance without defects.
Implementation Method 1
a thermal-curable resin and an inorganic filler... wherein the organic resin is a thermal-curable resin
Implementation Method 2
low thermal coefficient of dielectric constant (TCDk)... the first dielectric layer has a thermal coefficient of dielectric constant (TCDk) not higher than −150 ppm/° C.
Data Source
AI summary
A dielectric composite is provided. The dielectric composite includes:at least one first dielectric layer; andat least one second dielectric layer,wherein the first dielectric layer has a thermal coefficient of dielectric constant (TCDk) not higher than −150 ppm/° C., and the second dielectric layer has a TCDK not lower than 50 ppm/° C.; andthe dielectric composite has a dielectric constant (Dk) not lower than 4, and a TCDk ranging from 0 to −150 ppm/° C.