Self-Aligned Gate Endcaps for Dense Gate-All-Around Layouts
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Solution Overview
Problem
Conventional semiconductor manufacturing processes face challenges in scaling down transistor dimensions due to limitations in lithographic patterning, leading to increased gate endcap overlap and dynamic energy consumption, which degrades performance and limits layout density.
Innovation Solution
The implementation of self-aligned gate endcap (SAGE) architectures with gate-all-around devices above insulator substrates, where disposable spacers are used to determine gate endcap and contact overlap dimensions, eliminating the need for extra endcap length to account for mask registration errors and allowing for more aggressive diffusion spacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional lithographic patterning is used to pattern transistor features, then manufacturing process simplicity is maintained, but layout density decreases due to increased gate endcap overlap
Solution Approach 1:
The gate endcap isolation structures are formed preliminarily before the gate electrode deposition, using disposable spacers as templates. This preliminary formation of isolation structures at defined positions eliminates the need for mask registration during gate patterning, enabling tighter spacing between adjacent transistors while maintaining manufacturing simplicity through sequential processing steps.
Solution Approach 2:
Disposable spacers serve as intermediary structures that define the precise position of gate endcap isolation structures. These spacers act as temporary templates that mediate between the lithographic pattern and the final gate structure, enabling accurate placement without direct lithographic definition of the endcap regions.
2Manufacturing precision
If gate endcap overlap is increased to account for mask registration errors, then manufacturing precision is improved, but dynamic energy consumption increases
Solution Approach 1:
The gate endcap isolation structures are self-aligned to the gate electrode through the disposable spacer template, eliminating the need for additional mask registration steps. This self-alignment mechanism inherently provides precise positioning without requiring oversized endcap regions, thereby reducing parasitic capacitance and dynamic energy consumption while ensuring manufacturing precision.
3Area of moving object
If feature size is scaled down to increase device density, then capacity increases, but lithographic process constraints become overwhelming
Solution Approach 1:
The solution moves the critical dimension definition from the lithographic plane to the vertical dimension through disposable spacer thickness. By controlling spacer thickness through deposition processes rather than lithographic patterning, the method enables sub-lithographic feature sizes and tighter spacing without increasing lithographic process complexity.
Data Source
AI summary
Self-aligned gate endcap (SAGE) architectures with gate-all-around devices above insulator substrates, and methods of fabricating self-aligned gate endcap (SAGE) architectures with gate-all-around devices above insulator substrates, are described. In an example, an integrated circuit structure includes a semiconductor nanowire above an insulator substrate and having a length in a first direction. A gate structure is around the semiconductor nanowire, the gate structure having a first end opposite a second end in a second direction, orthogonal to the first direction. A pair of gate endcap isolation structures is included. The first of the pair of gate endcap isolation structures is directly adjacent to the first end of the gate structure, and the second of the pair of gate endcap isolation structures is directly adjacent to the second end of the gate structure.