RF Antenna Routing Rules to Protect Gate Dielectric Integrity
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Solution Overview
Problem
Conventional RF device fabrication faces issues with metal interconnections used as antennas causing charge accumulation, leading to leakage and damage to the gate dielectric layer, particularly due to increased area of metal interconnections which results in performance degradation.
Innovation Solution
The method involves forming a gate structure on a substrate, source/drain regions, and metal routings where the sum of the areas of the first and second metal routings divided by the area of the gate structure is controlled to be less than a specific ratio, ensuring balanced distribution and minimizing charge accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the area of metal interconnections is increased, then the charge collecting capability is improved, but the leakage and damage to gate dielectric layer worsens
Solution Approach 1:
The patent divides the metal interconnection structure into multiple segments with different functions: antenna elements for charge collection, isolation structures to prevent charge accumulation, and controlled connection points to the gate structure. This segmentation allows the antenna to collect charges while preventing harmful charge accumulation that would damage the gate dielectric layer.
Solution Approach 2:
The patent extracts and separates the antenna function from the standard metal interconnection layer by creating dedicated antenna structures with specific geometric patterns and connection rules. This extraction allows independent optimization of charge collection capability while maintaining control over the interaction with the gate structure, preventing dielectric damage.
2Quantity of substance
If the area of metal interconnections is increased, then the antenna effect is enhanced, but the leakage current increases
Solution Approach 1:
The patent introduces intermediary structures between the metal interconnections and the gate structure, including isolation regions and controlled via structures. These intermediaries mediate the interaction by providing controlled charge transfer paths that prevent excessive charge accumulation and reduce leakage current while maintaining the antenna effect.
Solution Approach 2:
The patent changes critical parameters of the metal interconnection structure including the area ratio between antenna metal and gate structure (controlled through specific layout rules), the geometry of connection points, and the spacing between antenna elements. These parameter changes optimize the antenna effect while keeping leakage current within acceptable limits.
3Productivity
If the metal routing area is increased, then the signal transmission capability is improved, but the charge accumulation worsens
Solution Approach 1:
The patent segments the metal routing into distinct functional zones: antenna regions for charge collection, transmission regions for signal routing, and isolation regions to prevent charge accumulation. This segmentation allows each zone to be optimized for its specific function while preventing harmful interactions between them.
Solution Approach 2:
The patent applies different geometric patterns, material properties, and connection rules to different local regions of the metal routing structure. Antenna regions have patterns optimized for charge collection, while transmission regions have patterns optimized for signal integrity, and connection regions have controlled impedance and spacing to prevent charge accumulation.
Data Source
AI summary
A method for determining antenna rule for a radio-frequency (RF) device includes the steps of forming a gate structure on a substrate, forming a source/drain region adjacent to the gate structure, forming a first metal routing on the source/drain region, and then forming a second metal routing on the gate structure. Preferably, a sum of an area of the first metal routing and an area of the second metal routing divided by an area of the gate structure is less than a ratio.