Continuous Replacement Gate Segmentation for Sub-30nm Spacing
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Solution Overview
Problem
The challenge lies in achieving smaller physical gate end-to-end spacing in semiconductor structures, as current methods, such as replacement gate processes, face difficulties in scaling and often result in shorting of gate structures, limiting device density and performance.
Innovation Solution
The method involves forming a continuous replacement gate structure within a trench, segmenting it into separate structures, and filling the end-to-end spacing with insulator material, allowing for reduced spacing of approximately 30 nm or less, independent of multiple exposure processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If replacement gate processes (exposure, etching, deposition) are used to form gate structures, then gate structures can be formed, but end to end spacing increases and device density decreases
Solution Approach 1:
A continuous gate structure is formed preliminarily across the entire semiconductor substrate before any segmentation occurs. This preliminary continuous structure ensures uniform formation and proper spacing control, after which mandrels are selectively removed to create final segmented gates with precise end-to-end spacing.
Solution Approach 2:
The continuous gate structure is segmented into individual gate regions by selectively removing mandrels from isolation regions. This segmentation process divides the initially continuous conductive layer into discrete gates separated by insulator material, achieving the required end-to-end spacing while maintaining manufacturing precision.
2Ease of manufacture
If multiple exposure and process steps are used in replacement gate formation, then gate structures can be formed, but process complexity increases and manufacturing precision deteriorates
Solution Approach 1:
Multiple gate formation operations are merged into a single continuous gate structure formation step. Instead of forming each gate independently through separate exposure and deposition steps, the entire gate layer is formed continuously in one process, reducing step count and improving spacing precision.
Solution Approach 2:
Mandrels serve as intermediary structures that guide the formation of the continuous gate structure and are later removed to create the final segmented gates. These temporary structures enable precise spacing control without requiring multiple direct exposure steps on the final gate pattern.
3Productivity
If physical gate end to end spacing is reduced to increase device density, then device density improves, but gate structures may short due to process limitations
Solution Approach 1:
Insulator material serves as an intermediary barrier between adjacent gate structures. This material is deposited in the spaces where mandrels were removed, physically separating the gates and preventing shorting while enabling reduced end-to-end spacing for higher device density.
Solution Approach 2:
The continuous gate structure is formed preliminarily with built-in spacing considerations, and insulator material is deposited in advance in the separation regions before final gate segmentation. This preliminary placement of insulators ensures gate integrity is maintained from the outset.
Data Source
AI summary
Gate structures and methods of manufacturing is disclosed. The method includes forming a continuous replacement gate structure within a trench formed in dielectric material. The method further includes segmenting the continuous replacement gate structure into separate replacement gate structures. The method further includes forming insulator material between the separate replacement gate structures.