Multi-directional Gate Wiring via Replacement Gate Trench Etch
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Solution Overview
Problem
The challenge of printing gate patterns with small pitches leads to unidirectional gate patterns, shifting the burden of signal routing to metal interconnect structures, which limits the extension of gate lines in semiconductor technologies.
Innovation Solution
A post-planarization recess etch process is combined with a replacement gate scheme to enable the formation of multi-directional wiring in gate electrode lines by forming trenches between disposable gate structures and replacing them with gate stack structures that extend in different horizontal directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If unidirectional gate patterns are used to overcome lithographic minimum dimension limits, then gate pattern printing becomes feasible, but signal routing capability is reduced and burden on metal interconnect structures increases
Solution Approach 1:
The patent transitions from unidirectional gate lines to multi-directional gate lines that extend in multiple horizontal directions (e.g., first horizontal direction and second horizontal direction perpendicular thereto). This dimensional change in gate line configuration enables signal routing capabilities previously requiring metal interconnects, thereby resolving the contradiction between manufacturability and routing versatility.
Solution Approach 2:
The gate structure is designed to serve multiple functions: it acts as both the transistor gate electrode and a signal routing conduit. By enabling gate lines to extend in multiple directions and form contiguous conductive paths, the gate structure assumes the additional function of signal distribution, reducing the burden on metal interconnect structures.
2Ease of manufacture
If disposable gate structures are formed with standard lithographic patterns, then manufacturing process is simple, but multi-directional wiring configuration cannot be achieved
Solution Approach 1:
The gate structure is divided into disposable gate structures (formed by standard lithography) and replacement gate structures (formed by trench filling). The disposable structures serve as temporary placeholders that define the eventual multi-directional gate geometry. This segmentation allows standard lithographic processes to be combined with advanced trench-based formation methods to achieve multi-directional wiring.
Solution Approach 2:
Disposable gate structures are formed in advance using standard lithographic patterns, establishing the preliminary geometry for the final multi-directional gate configuration. These preliminary structures guide subsequent trench formation and replacement gate deposition, enabling complex multi-directional wiring to be built upon simple initial patterns.
3Ease of manufacture
If gate lines are constrained to single direction, then lithographic printing is easier, but lateral connections in metal interconnect structures must be increased
Solution Approach 1:
The patent merges the gate electrode function with the signal routing function by creating contiguous gate level structures that extend in multiple directions. This consolidation eliminates the need for separate lateral connections in metal interconnect structures, as the multi-directional gate lines themselves provide the routing pathways, thereby reducing metal interconnect complexity.
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 allows for the creation of contiguous gate level structures with portions extending along multiple horizontal directions, reducing the burden on metal interconnects and enhancing signal routing capabilities.
Implementation Method 1
a trench extending between two disposable gate structures are formed by a combination of lithographic methods and an anisotropic etch
Data Source
AI summary
A post-planarization recess etch process is employed in combination with a replacement gate scheme to enable formation of multi-directional wiring in gate electrode lines. After formation of disposable gate structures and a planarized dielectric layer, a trench extending between two disposable gate structures are formed by a combination of lithographic methods and an anisotropic etch. End portions of the trench overlap with the two disposable gate structures. After removal of the disposable gate structures, replacement gate structures are formed in gate cavities and the trench simultaneously. A contiguous gate level structure can be formed which include portions that extend along different horizontal directions.