FinFET Isolation Layout Using Self-Aligned Intersecting Trenches
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Solution Overview
Problem
Current semiconductor manufacturing techniques face challenges in reducing the area penalty and increasing costs due to the need for extensive isolation between FinFETs, which occupy more space and require multiple dummy gates, complicating the overlay in patterning and lithography processes.
Innovation Solution
The proposed semiconductor arrangement and manufacturing method involve forming FinFETs with self-aligned isolation parts that intersect the gate stacks, reducing the footprint of isolation by using a single dummy gate and improving overlay in patterning, achieved through specific etching and dielectric material filling processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extensive isolation is used between FinFETs, then device isolation is improved, but area occupancy increases and manufacturing cost increases
Solution Approach 1:
The patent merges the isolation structure with the FinFET structure by forming the isolation part within the same trench as the FinFET, eliminating the need for separate isolation regions. This integration reduces the total area occupied by isolation while maintaining effective device isolation through the shared trench structure.
Solution Approach 2:
The patent transitions from planar isolation to three-dimensional isolation by forming isolation parts that extend vertically within the trench structure. This vertical dimension allows isolation to be achieved without increasing horizontal footprint, as the isolation material fills the trench space below and around the FinFET structure.
2Reliability
If multiple dummy gates are used for isolation, then device isolation is improved, but device complexity increases
Solution Approach 1:
The patent extracts the dummy gate function from the isolation structure, eliminating the need for separate dummy gates. The isolation is achieved purely through the trench structure and isolation material, separating the isolation function from gate structures and reducing overall device complexity.
Solution Approach 2:
The trench structure serves multiple functions simultaneously: it provides mechanical support, electrical isolation, and stress control for the FinFET channel. This multi-functionality eliminates the need for separate dummy gates that would otherwise be required for isolation, simplifying the overall device structure.
3Reliability
If extensive isolation with multiple dummy gates is used, then device isolation is improved, but overlay precision in patterning deteriorates
Solution Approach 1:
The patent performs preliminary actions by forming the isolation trench and filling it with isolation material before final gate patterning steps. This sequence establishes stable reference structures early in the process, improving subsequent overlay precision by providing robust alignment features for later lithography steps.
Data Source
AI summary
Semiconductor arrangements and methods of manufacturing the same. The semiconductor arrangement may include: a substrate including a base substrate, a first semiconductor layer on the substrate, and a second semiconductor layer on the first semiconductor layer; first and second fin structures formed on the substrate and extending in the same straight line, each of the first and second fin structures including at least portions of the second semiconductor layer; a first isolation part formed around the first and second fin structures on opposite sides of the straight line; first and second FinFETs formed on the substrate based on the first and second fin structures respectively; and a second isolation part between the first and second fin structures and intersecting the first and second fin structures to isolate the first and second fin structures from each other.