Dummy Fin Etch-Stop Structure for Self-Aligned GAA Transistors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices face challenges in achieving higher device density, performance, and lower costs as they transition into nanometer technology process nodes, particularly in three-dimensional designs.
Innovation Solution
The development of a semiconductor device structure that includes a first and second fin structure with a dummy fin structure in between, featuring an etching stop layer to protect underlying layers and enable self-aligned patterning, allowing for the formation of gate-all-around transistor structures with improved alignment and reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional lithography patterning is used for three-dimensional structures, then manufacturing process complexity increases due to alignment requirements, but device density and performance cannot be sufficiently improved
Solution Approach 1:
The method performs preliminary patterning actions by forming mandrels and spacers in a self-aligned manner before final gate patterning. The spacers are formed conformally on the mandrels, and the mandrels are removed to create precisely positioned cavities, eliminating the need for complex alignment steps during gate formation.
Solution Approach 2:
The invention uses mandrels as intermediary structures to define the positions of cavities and spacers. These mandrels serve as temporary mediators that guide the formation of critical structures, enabling precise positioning without direct alignment between separate patterning steps.
2Productivity
If higher device density is pursued through three-dimensional designs, then fabrication challenges and process complexity increase, but performance and cost targets cannot be met
Solution Approach 1:
The invention transitions from two-dimensional planar transistor designs to three-dimensional structures by forming vertical cavities and gate-all-around transistor configurations. This dimensional change enables higher device density by utilizing vertical space while maintaining manufacturability through self-aligned processes.
Solution Approach 2:
The method segments the transistor structure into distinct functional regions: mandrels for cavity definition, spacers for lateral confinement, and gate structures for channel control. This segmentation enables independent optimization of each component while simplifying the overall fabrication process through modular self-aligned formation.
3Reliability
If conventional patterning methods are used for gate structures, then alignment complexities increase, but device performance cannot be optimized
Solution Approach 1:
The patterning process is made self-service through self-alignment mechanisms where previously formed structures (mandrels and spacers) automatically define the positions of subsequent structures. The spacers form conformally on the mandrels, and their positions are determined by the mandrel geometry rather than requiring separate alignment steps, thereby simplifying the process while improving device performance.
Data Source
AI summary
A method for forming a semiconductor device structure is provided. The semiconductor device structure includes a first fin structure formed over a substrate, and the first fin structure includes a plurality of first nanostructures stacked in a vertical direction. The semiconductor device structure further includes a second fin structure formed over the substrate, and the second fin structure includes a plurality of second nanostructures stacked in a vertical direction. The semiconductor device structure further includes a dummy fin structure between the first fin structure and the second fin structure. The dummy fin structure includes a first etching stop layer between a bottom portion and a top portion.