GAA Gate Structure Layout for Precise Resistance Extraction
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Solution Overview
Problem
Conventional methods for extracting gate resistance of gate-all-around (GAA) devices are imprecise due to the measurement of current flow primarily through the top portions of gate structures, neglecting the higher resistance between nanosheets, which affects the precision of resistance calculation.
Innovation Solution
The proposed method involves connecting gate structures through connection structures under isolation features, allowing current to flow through the portions between nanosheets, enabling precise extraction of gate resistance by measuring total resistance and subtracting the resistance of connection structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to extract gate resistance of GAA devices, then the measurement process is simple, but the measurement precision deteriorates because current flow is measured primarily through top portions of gate structures, neglecting higher resistance between nanosheets
Solution Approach 1:
The measurement structure is segmented into distinct components: connection structures with first contacts for individual gate lines, and second contacts for combining gate lines. This segmentation allows separate measurement and calculation of connection structure resistance versus gate structure resistance, improving measurement precision by isolating the measurement path through nanosheet regions.
Solution Approach 2:
Connection structures serve as intermediary elements that facilitate current flow between gate structures while having measurable resistance. These intermediaries (connection structures with contacts) enable precise measurement by providing known resistance paths that can be subtracted from total resistance measurements to isolate gate resistance.
2Measurement precision
If gate structures are connected through connection structures under isolation features, then the measurement precision improves by allowing current to flow through portions between nanosheets, but the device complexity increases
Solution Approach 1:
Connection structures and contacts are formed preliminarily during the fabrication process, integrating the measurement path into the device structure before final testing. This preliminary action embeds the measurement capability into the fabrication flow, reducing later manufacturing complexity despite the added structural elements.
Solution Approach 2:
The connection structures serve multiple functions: they electrically connect gate structures for operation, provide measurement paths for resistance extraction, and are integrated within isolation features for spatial organization. This multi-functionality reduces the need for separate dedicated measurement structures, easing manufacturing.
3Reliability
If conventional measurement methods are used, then the manufacturing process remains simple, but the reliability of device operation speed design deteriorates due to inaccurate RC time delay calculations
Solution Approach 1:
The measurement approach substitutes direct physical measurement of gate resistance with an indirect calculation method: measuring total resistance through connection structures and gate structures, then subtracting known connection structure resistance to derive gate resistance. This substitution enables reliable RC time delay calculations without requiring complex direct measurement apparatus.
Data Source
AI summary
A semiconductor device includes: a first transistor including a first gate structure; a second transistor including a second gate structure and arranged adjacent to the first transistor in a first direction; and a first isolation feature extending in a second direction. The second direction and the first direction are perpendicular. The first isolation feature is between the first gate structure and the second gate structure and in contact with the first gate structure and the second gate structure. The semiconductor structure further includes a first connection structure under the first isolation feature. The first connection structure connects the first gate structure to the second gate structure.