Multilayer Wiring Substrate Graphite Sheet Resin Layer
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Solution Overview
Problem
Existing multilayer wiring substrates for radio-frequency signals face issues with unintended circuit paths and noise due to stray capacitance and resonance caused by graphite sheets, leading to failure in providing desired characteristics.
Innovation Solution
A multilayer wiring substrate design that includes a dielectric base body with a signal line, a ground conductor, and a graphite sheet, where the graphite sheet is positioned to prevent electric field penetration and resonance, ensuring intended circuit paths and enhanced thermal dissipation without forming unintended paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a graphite sheet is embedded in the base material for heat dissipation, then thermal dissipation is improved, but unintended circuit paths and noise are generated due to stray capacitance and resonance
Solution Approach 1:
A resin layer is introduced as an intermediary substance between the graphite sheet and the conductor layer. This resin layer has lower dielectric constant than air, thereby reducing stray capacitance between the graphite sheet and conductor layer. The resin layer acts as a mediator that allows thermal contact while electrically isolating the components to prevent unintended circuit paths and resonance issues
Solution Approach 2:
The invention changes the dielectric parameter by filling the gap between the graphite sheet and conductor layer with resin material having specific dielectric properties. This parameter change reduces the stray capacitance compared to having an air gap, thereby improving circuit characteristics while maintaining thermal dissipation functionality
2Temperature
If the graphite sheet is positioned close to the conductor layer for thermal contact, then heat dissipation is enhanced, but stray capacitance increases causing unintended circuit paths
Solution Approach 1:
The resin layer serves as a dual-function intermediary: it provides thermal conduction path between the graphite sheet and conductor layer for efficient heat dissipation, while simultaneously providing electrical isolation to reduce stray capacitance. This mediator enables close positioning without the harmful electrical effects
3Manufacturing precision
If metal is used in the guide member for positioning the graphite sheet, then positioning precision is improved, but resonance and noise are generated in radio-frequency circuits
Solution Approach 1:
The invention changes the material parameter of the guide member from metal to resin, which has different electromagnetic properties. The resin material does not conduct electricity and does not resonate at radio frequencies, thereby eliminating the harmful resonance and noise effects while maintaining the positioning function through mechanical means
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
This design effectively reduces the possibility of unintended circuit paths and noise, maintaining desired characteristics by positioning the graphite sheet to prevent electric field penetration and resonance, while enhancing thermal dissipation properties.
Implementation Method 1
a graphite sheet in the dielectric base body... enable dissipation of heat
Data Source
AI summary
A multilayer wiring substrate according to the present invention includes a dielectric base body, a signal line in or on the dielectric base body, a ground conductor in the dielectric base body, and a graphite sheet in the dielectric base body. The dielectric base body is a laminate including dielectric sheets stacked on top of each other. The ground conductor and the signal line face each other in a stacking direction of the dielectric sheets. The ground conductor overlaps the signal line when viewed in plan in the stacking direction. The graphite sheet and the signal line face each other in the stacking direction without the signal line being located between the graphite sheet and the ground conductor. An upper surface of the graphite sheet is coplanar with an upper surface of the ground conductor or is located below the upper surface of the ground conductor.