Stacked Coplanar Waveguides for Impedance Control
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Solution Overview
Problem
Conventional coplanar wave-guides in integrated circuits face limitations in reducing energy loss and adjusting characteristic impedance due to their formation in a single layer, which restricts flexibility and quality.
Innovation Solution
A novel coplanar wave-guide structure is formed by stacking portions in multiple dielectric layers, allowing for increased thickness and adjustment of signal and ground lines across different layers, utilizing various materials and processes like single or dual damascene for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the wave-guide is formed in the top layer far from the substrate, then the energy loss in substrate is reduced, but the vertical distance increase is very small compared to the wavelength and the effect is limited
Solution Approach 1:
The wave-guide structure transitions from a single-layer planar configuration to a multi-layer stacked configuration, utilizing the vertical dimension across multiple dielectric layers to achieve greater effective distance from the substrate while maintaining lateral integration
2Ease of manufacture
If the ground lines thickness is determined by chip manufacturing process, then the manufacturing is simplified, but the characteristic impedance adjustment is limited
Solution Approach 1:
The wave-guide structure is divided into multiple segments across different dielectric layers, with each layer's conductive lines independently controllable in thickness and dimensions, allowing characteristic impedance adjustment while maintaining standard manufacturing processes
Solution Approach 2:
The characteristic impedance is adjusted by varying the thickness and dimensions of conductive lines in different dielectric layers, enabling continuous impedance control through geometric parameter modification rather than material changes
Data Source
AI summary
An integrated circuit structure includes a semiconductor substrate; an interconnect structure over the semiconductor substrate; a first dielectric layer over the semiconductor substrate and in the interconnect structure; a second dielectric layer in the interconnect structure and over the first dielectric layer; and a wave-guide. The wave-guide includes a first portion in the first dielectric layer and a second portion in the second dielectric layer. The first portion adjoins the second portion.