Gate Isolation Layout Using Dummy Fins for Dense FinFET Patterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for forming gate cut features in semiconductor fabrication face challenges in spacing and alignment due to fixed depth constraints, limiting the ability to design complex patterns and increase pattern density in field-effect transistors like GAA and FinFETs.
Innovation Solution
The introduction of dielectric dummy fin structures between functional fin structures allows for the formation of gate layers that can be etched to expose top surfaces, enabling the deposition of a conductive layer to connect gate segments and the use of cut features over dummy fin structures to electrically isolate adjacent gate segments, thereby improving spacing and alignment constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form gate cut features, then the fabrication process is simple, but spacing and alignment constraints limit pattern density
Solution Approach 1:
A dielectric intermediary layer is introduced between the substrate and the gate structure. This intermediary layer enables the formation of cut features at different depths, allowing precise spacing and alignment control without directly modifying the gate structure itself. The intermediary acts as a mediator that decouples the spacing requirements from the gate feature fabrication constraints.
Solution Approach 2:
The invention transitions from two-dimensional planar patterning to three-dimensional vertical patterning by forming cut features at different depths within the dielectric intermediary layer. This dimensional change allows multiple cut features to be stacked vertically, increasing pattern density without compromising horizontal spacing and alignment precision.
2Adaptability or versatility
If fixed depth constraints are applied to gate cut features, then the fabrication process is straightforward, but design flexibility for complex patterns is limited
Solution Approach 1:
The gate cut features are segmented into multiple depth levels within the dielectric intermediary layer. Each segment can be independently formed and controlled, allowing diverse pattern designs to be created by selectively activating different depth segments. This segmentation maintains fabrication simplicity by using standard deposition and etching processes applied in sequence.
Solution Approach 2:
The invention introduces dynamic control over cut feature depth and positioning by varying the etch depth into the dielectric intermediary layer. This dynamic adjustment capability allows the same fabrication process to produce different pattern configurations, enhancing design flexibility without requiring fundamentally different manufacturing approaches.
3Productivity
If fin structures are spaced closer together, then pattern density increases, but overlay constraints for cut features worsen
Solution Approach 1:
By moving cut feature formation into the vertical dimension within the dielectric intermediary layer, the invention eliminates the direct conflict between horizontal fin spacing and overlay constraints. Cut features at different vertical levels can be formed with relaxed overlay requirements, enabling closer horizontal fin spacing while maintaining manufacturing precision.
Solution Approach 2:
The dielectric intermediary layer serves as a buffer that decouples the overlay precision requirements from the final gate cut feature alignment. By forming cut features within this intermediary layer rather than directly in the gate structure, the overlay constraints are significantly reduced, allowing higher pattern density with maintained precision.
Data Source
AI summary
A semiconductor structure includes a plurality of fin structures extending along a first direction, a plurality of gate structure segments positioned along a line extending in a second direction, the second direction being orthogonal to the first direction, wherein the gate structure segments are separated by dummy fin structures. The semiconductor structure further includes a conductive layer disposed over both the gate structure segments and the dummy fin structures to electrically connect at least some of the gate structure segments, and a cut feature aligned with one of the dummy fin structures and positioned to electrically isolate gate structure segments on both sides of the one of the dummy fin structures.