Nanosheet Gate Separator Structure to Prevent Gate Bridging
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Solution Overview
Problem
The scaling down of Integrated Circuit (IC) technology has increased complexity in processing and manufacturing, particularly for multi-gate devices, where challenges arise in forming gate structures on multiple sides of a channel region without voids or seams, which can lead to abnormal bridging and yield issues.
Innovation Solution
The formation of a separator structure, also known as a cut metal gate (CMG) structure, is implemented to separate gate stacks from each other, ensuring they are free of voids or seams, thereby preventing abnormal bridging and improving manufacturing yield. This is achieved through a process involving the formation of spacers, a body, and a cap structure within the semiconductor device fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-gate devices are introduced to replace planar transistors to increase functional density, then production efficiency and cost are improved, but processing and manufacturing complexity increases
Solution Approach 1:
The gate structure is segmented into multiple gates positioned on different sides of the channel region (e.g., gate-on-top, gate-on-side, gate-under configurations). This segmentation allows each gate to be formed and controlled independently, managing the complexity of multi-gate device fabrication while achieving higher functional density and improved production efficiency
Solution Approach 2:
Multiple gate structures are nested around the channel region in a hierarchical arrangement, with gates at different vertical and horizontal positions. The channel region is nested within the gate structures, creating a compact multi-gate configuration that increases functional density without proportionally increasing processing complexity
2Quantity of substance
If gate structures are formed on multiple sides of the channel region to create multi-gate devices, then functional density is increased, but voids or seams may form leading to abnormal bridging and yield issues
Solution Approach 1:
A separator structure is formed in advance between adjacent gate structures before the gate electrodes are deposited. This preliminary action prevents voids or seams from forming during subsequent processing steps, ensuring continuous coverage and preventing abnormal bridging, thereby maintaining high manufacturing yield while achieving increased functional density
Solution Approach 2:
The separator structure acts as an intermediary element between adjacent gate structures, filling the spaces that would otherwise form voids or seams. This intermediary component ensures proper spacing and continuous material coverage, preventing abnormal bridging between gates while allowing high functional density through compact multi-gate configuration
Data Source
AI summary
Provided are a semiconductor device and a method of forming the same. The semiconductor device includes a semiconductor device. The semiconductor device includes a substrate including a plurality of fins, a plurality of semiconductor nanosheets stacked on the plurality of fins, a plurality of gate stacks wrapping the plurality of semiconductor nanosheets, an isolation structure around the plurality of fins, and a separator structure on the isolation structure to separate the plurality of gate stacks from each other. The separator structure includes a body and a cap on the body. The cap includes a first portion and a second portion. Sidewalls and bottom of the second portion is wrapped by the first portion.