FinFET Gate Isolation Structure With Dielectric Plug Trenches
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing complexity of semiconductor integrated circuit (IC) manufacturing due to scaling down processes, particularly in forming FinFET devices, requires advanced methods to achieve efficient and precise patterning and isolation of semiconductor fins and transistors while preventing leakage current.
Innovation Solution
The method involves forming semiconductor fins on a substrate using photolithography and self-aligned processes, followed by the creation of isolation structures, dummy gate stacks, and dielectric plugs to replace the dummy gates, ensuring precise control over etching processes to form recesses and gate trenches, which allows for the formation of a dielectric plug that provides effective isolation between source/drain features and transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scaling down process is used to increase functional density, then production efficiency and cost are improved, but processing complexity increases
Solution Approach 1:
The patent segments the gate structure into multiple layers (first gate layer, second gate layer) and divides the isolation approach into distinct components (dielectric plugs in trenches, lateral dielectric structures). This segmentation allows each component to be optimized independently for the scaled-down geometry while managing the overall processing complexity through modular fabrication steps.
Solution Approach 2:
The patent transitions from planar gate structures to three-dimensional multi-layer gate configurations. By adding vertical dimensionality with stacked gate layers and incorporating dielectric plugs at different depths (including extending into substrate), the design achieves higher functional density without simply reducing lateral dimensions, thereby managing processing complexity differently.
2Productivity
If FinFET structure is used to replace planar transistor, then functional density is improved, but manufacturing complexity increases
Solution Approach 1:
The FinFET manufacturing process is segmented into distinct phases: forming the fin structure, creating the first gate layer, forming dielectric plugs in trenches, adding the second gate layer, and implementing lateral dielectric structures. Each segment addresses specific functional requirements independently, allowing optimization of functional density while managing manufacturing complexity through systematic process breakdown.
Solution Approach 2:
Dielectric plugs are formed in trenches before the final gate structure is completed, and lateral dielectric structures are prepared in advance. These preliminary actions establish the isolation framework early in the manufacturing process, simplifying subsequent steps and reducing overall manufacturing complexity while enabling the desired FinFET functional density.
3Reliability
If isolation structures are formed to prevent leakage current, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements isolation with local quality by placing dielectric plugs specifically in trenches at critical locations where leakage prevention is most needed, and adding lateral dielectric structures only where required for source/drain feature isolation. This targeted approach achieves high reliability for leakage prevention without unnecessarily increasing overall device structure complexity throughout the entire device.
Solution Approach 2:
The isolation structure uses a nested configuration where dielectric plugs are embedded within trenches that are themselves integrated into the FinFET structure, and lateral dielectric structures are positioned adjacent to and complementary with the vertical dielectric plugs. This nesting achieves comprehensive isolation coverage with compact structures, improving reliability while minimizing the increase in device complexity.
4Manufacturing precision
If photolithography and self-aligned processes are used, then manufacturing precision is improved, but processing complexity increases
Solution Approach 1:
Self-aligned structures are prepared in advance during earlier fabrication steps, establishing reference features that guide subsequent photolithography patterning. This preliminary preparation ensures that critical dimensions and alignments are achieved with high precision while reducing the complexity of later alignment-critical steps, as the self-aligned references eliminate the need for additional complex alignment procedures.
Data Source
AI summary
A device includes a first transistor, a second transistor, and a dielectric structure. The first transistor is over a substrate and has a first gate structure. The second transistor is over the substrate and has a second gate structure. The dielectric structure is between the first gate structure and the second gate structure. The dielectric structure has a width increasing from a bottom position of the dielectric structure to a first position higher than the bottom position of the dielectric structure. A width of the first gate structure is less than the width of the dielectric structure at the first position.