Active Gate Contact Layout With Metal Oxide Caps Against Shorting
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Solution Overview
Problem
The scaling of multi-gate transistors in integrated circuits faces challenges due to variability in conventional fabrication processes, leading to constraints in further miniaturization, particularly in forming gate contacts over active regions without shorting to adjacent source or drain regions.
Innovation Solution
The implementation of metal oxide cap structures to inhibit shorting during the fabrication of contact over active gate (COAG) structures, where a metal oxide layer is selectively grown on trench contact structures to serve as an etch stop and insulating layer, allowing for relaxed edge placement errors and direct contact formation on active gate portions without additional lithographic steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fabrication processes are used for scaling multi-gate transistors, then manufacturing simplicity is maintained, but manufacturing precision deteriorates due to variability at 10 nanometer node or sub-10 nanometer node range
Solution Approach 1:
A metal oxide cap structure is formed on the trench contact structure before the gate contact etching process. This preliminary formation of the cap structure prevents etch penetration into the source/drain regions, thereby enabling precise gate contact formation at 10nm node or sub-10nm node range without shorting to adjacent source or drain regions.
2Area of stationary object
If gate contacts are formed directly over active regions, then area efficiency is improved, but reliability deteriorates due to shorting risk to adjacent source or drain regions
Solution Approach 1:
The metal oxide cap structure serves as an intermediary protective layer between the gate contact and the source/drain regions. This cap structure allows the gate contact to be positioned directly over the active region for area efficiency while simultaneously preventing electrical shorting to adjacent source or drain regions through its insulating properties.
3Reliability
If additional lithographic steps are added to prevent shorting, then reliability is improved, but productivity deteriorates due to increased process steps
Solution Approach 1:
The metal oxide cap structure is integrated into the existing trench contact formation process, combining the functions of contact formation and shorting prevention into a single process sequence. This eliminates the need for additional lithographic steps while maintaining reliability through the cap structure that prevents etch penetration during gate contact formation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables improved edge placement margins for gate vias, reduces the risk of shorting, and allows for larger gate via sizes with lower resistance, facilitating the scaling of integrated circuits while maintaining layout efficiency.
Implementation Method 1
a metal oxide layer is selectively grown on trench contact structures to serve as an etch stop and insulating layer
Data Source
AI summary
Contact over active gate structures with metal oxide cap structures are described. In an example, an integrated circuit structure includes a plurality of gate structures above substrate, each of the gate structures including a gate insulating layer thereon. A plurality of conductive trench contact structures is alternating with the plurality of gate structures, each of the conductive trench contact structures including a metal oxide cap structure thereon. An interlayer dielectric material is over the plurality of gate structures and over the plurality of conductive trench contact structures. An opening is in the interlayer dielectric material and in a gate insulating layer of a corresponding one of the plurality of gate structures. A conductive via is in the opening, the conductive via in direct contact with the corresponding one of the plurality of gate structures, and the conductive via on a portion of one or more of the metal oxide cap structures.