Dielectric-Lined Trench Contacts for Shorting Margin at Sub-10 nm
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Solution Overview
Problem
Current integrated circuit fabrication processes face challenges in scaling to sub-10 nanometer nodes due to variability in conventional methods, leading to constraints on semiconductor processes and increased risk of via shorting, which affects the yield and reliability of trench contact structures.
Innovation Solution
The implementation of lined conductive structures for trench contacts, where an inner liner is formed only in the orthogonal direction to the gate, reducing the edge placement error margin while preserving the via enclosure margin, thereby improving the shorting margin and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fabrication processes are used for scaling, then manufacturing simplicity is maintained, but manufacturing precision deteriorates due to variability at sub-10 nanometer nodes
Solution Approach 1:
The liner formation process is segmented to be applied only in the orthogonal direction to the gate, rather than uniformly in all directions. This segmentation allows precise control over edge placement error while preserving via enclosure margin, resolving the contradiction between manufacturing precision and process complexity.
Solution Approach 2:
The inner liner is selectively formed only in specific regions (orthogonal to gate) rather than uniformly throughout the trench contact structure. This local application of the liner provides enhanced alignment precision where needed while avoiding unnecessary complexity in other regions.
2Manufacturing precision
If liner thickness is increased to improve edge placement error margin, then manufacturing precision improves, but via enclosure margin is reduced
Solution Approach 1:
The liner is segmented to exist only in the orthogonal direction to the gate, creating distinct regions with different functional requirements. This segmentation allows the liner to improve edge placement error margin without encroaching on the via enclosure margin in other directions.
Solution Approach 2:
Different regions of the trench contact structure have different liner configurations: the orthogonal region has a liner for improved alignment precision, while other regions preserve the via enclosure margin. This local differentiation resolves the contradiction between the two competing margins.
3Reliability
If conventional trench contact structures are used, then process simplicity is maintained, but shorting risk increases at scaled dimensions
Solution Approach 1:
The inner liner acts as an intermediary dielectric layer between the conductive trench contact and surrounding structures. This intermediary layer provides electrical isolation that reduces shorting risk, while its selective placement minimizes the increase in structural complexity.
4Reliability
If full liner coverage is applied to trench contacts, then reliability improves through better isolation, but edge placement error margin is reduced
Solution Approach 1:
The liner coverage is segmented rather than continuous, being applied only in the orthogonal direction to the gate. This segmentation provides sufficient isolation reliability for reduced shorting risk while preserving edge placement error margin in critical regions where the liner is absent.
Data Source
AI summary
Lined conductive via structures for trench contact are described. In an example, an integrated circuit structure includes a plurality of gate structures over corresponding ones of a plurality of vertical stacks of horizontal nanowires. The integrated circuit structure also includes a plurality of conductive trench contact structures alternating with the plurality of gate structures, each of the plurality of conductive contact structures having an upper portion over a lower portion, the upper portion of each of the plurality of conductive trench contact structures having a length between ends. The integrated circuit structure also includes a dielectric liner in lateral contact with sides along the length of the upper portion of each of the plurality of conductive contact structures, wherein the dielectric liner is not in contact with the ends of the upper portion of each of the plurality of conductive contact structures.