Borosilicate Microsphere Circuit Substrates for Low Dissipation Factor
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Solution Overview
Problem
There is a need for low dielectric constant, low loss circuit materials with improved dissipation factors, particularly for high-frequency applications, as existing materials face supply constraints and variability with naturally sourced cenospheres, and synthetic alternatives have not met the required electrical properties.
Innovation Solution
The use of synthetic borosilicate microspheres treated with an alkaline solution to reduce sodium content, resulting in a dielectric substrate with a dielectric constant of less than 3.5 and a dissipation factor of less than 0.006 at 10 GHz, which are incorporated into a polymer matrix material for circuit subassemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If naturally sourced cenospheres are used as filler, then low dielectric constant and low cost are achieved, but supply availability and compositional consistency deteriorate
Solution Approach 1:
The patent creates a synthetic copy of naturally occurring cenospheres by manufacturing glass hollow microspheres that replicate the size, shape, and dielectric properties of natural cenospheres. This synthetic reproduction eliminates supply constraints and compositional variability while maintaining the desired low dielectric constant properties.
Solution Approach 2:
The patent controls and standardizes the physical and chemical parameters of the filler material through synthetic manufacturing. By precisely controlling particle size distribution, wall thickness, and glass composition during synthesis, the patent achieves consistent dielectric properties and compositional uniformity across production batches.
2Reliability
If synthetic glass hollow microspheres are used as filler, then supply availability and compositional consistency are improved, but dissipation factor performance deteriorates
Solution Approach 1:
The patent optimizes the chemical composition parameters of the glass matrix, specifically controlling the ratios of silica, boron oxide, and other oxides to achieve low dielectric loss. The synthetic process allows precise adjustment of composition parameters to minimize dissipation factor while maintaining low dielectric constant.
Solution Approach 2:
The patent creates a composite glass composition combining multiple oxide components in specific proportions. This composite material approach allows synergistic effects where the combination of different oxides achieves superior dissipation factor performance compared to single-component glass systems.
3Reliability
If hollow glass microspheres are used to reduce dielectric constant, then electrical properties are improved, but mechanical strength may deteriorate
Solution Approach 1:
The patent optimizes the local structure of the glass sphere walls, controlling wall thickness and density to balance dielectric performance and mechanical strength. By adjusting the local quality of the glass matrix in the sphere walls, the patent achieves sufficient structural integrity while maintaining low dielectric constant properties.
Solution Approach 2:
The patent uses composite glass compositions with reinforced oxide networks that provide both low dielectric constant and enhanced mechanical strength. The multi-component glass system creates a synergistic effect where certain oxides contribute to dielectric performance while others strengthen the glass matrix structure.
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 approach provides circuit subassemblies with superior electrical properties, including a low dissipation factor and improved Passive Intermodulation (PIM) performance, suitable for high-frequency applications, and offers a theoretically inexhaustible supply of synthetic materials.
Implementation Method 1
the borosilicate microspheres have been treated with an alkaline solution, thereby modifying the surface of the microspheres
Data Source
Figure 1~4
AI summary
A circuit subassembly is disclosed comprising a conductive metal layer and a dielectric substrate layer having a dielectric constant of less than about 3.5 and a dissipation factor of less than about 0.006 at 10 GHz, wherein the composition of the dielectric substrate layer comprises about 5 to about 70 volume percent of borosilicate microspheres that have been treated with an alkaline solution.