Semiconductor Word Line Layout for Bit Line Contact Window
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Solution Overview
Problem
The miniaturization of semiconductor devices poses challenges in maintaining performance due to reduced active area widths and pitches, leading to limitations in the fabrication process that fail to meet practical product requirements.
Innovation Solution
A semiconductor device design featuring a substrate with shallow trench isolation and active structures, where a first active area is surrounded by a second active area, and word lines are arranged with different pitches to improve the process window of bit line contacts and prevent direct conduction between bit lines and word lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pitch between active areas is reduced to increase device density, then the device integration is improved, but the fabrication process window deteriorates and performance cannot be maintained
Solution Approach 1:
The patent divides the active areas into two distinct types: first active areas with smaller pitch for high-density integration, and second active areas with larger pitch for improved fabrication process window. This segmentation allows different regions to serve different functional requirements, resolving the contradiction between density and manufacturability
Solution Approach 2:
Different pitch values are assigned to different spatial locations: the first active areas use a first pitch optimized for density, while the second active areas use a second pitch optimized for fabrication. This local differentiation enables each region to have the appropriate geometric characteristics for its intended purpose
2Productivity
If the active area width is reduced to increase device density, then the integration is improved, but the performance of small-sized elements deteriorates
Solution Approach 1:
The patent segments the active areas into first and second types with different dimensions. The first active areas have smaller widths for high-density integration, while the second active areas have larger widths that maintain adequate performance characteristics, thus resolving the contradiction between density and performance
Solution Approach 2:
Different width specifications are applied locally: first active areas use a first width for maximum density, while second active areas use a second width for performance assurance. This local quality differentiation ensures that performance-critical regions have sufficient dimensions
3Productivity
If the pitch between word lines is uniformly reduced, then the device density is improved, but the process window of bit line contacts deteriorates
Solution Approach 1:
The patent segments the word line array into first word lines with smaller pitch for density and second word lines with larger pitch for contact fabrication. This segmentation resolves the contradiction by allowing different pitch regimes in different regions
Solution Approach 2:
Different pitch values are assigned to different word line groups: first word lines use a first pitch for density optimization, while second word lines use a second pitch for contact process window optimization. This local differentiation resolves the contradiction between density and manufacturability
4Productivity
If the pitch between word lines is reduced, then the device density is improved, but direct conduction between bit lines and word lines occurs
Solution Approach 1:
The patent segments the word line structure into first and second word lines with different pitch values. The larger pitch of second word lines prevents direct conduction between bit lines and word lines, while the overall dense arrangement maintains high device density
Solution Approach 2:
Different pitch specifications are applied to different word line groups: first word lines use smaller pitch for density, while second word lines use larger pitch for electrical isolation. This local quality control prevents direct conduction in critical regions
Data Source
AI summary
The present disclosure relates to a semiconductor device and a fabricating method thereof, which includes a substrate and a plurality of word lines. The substrate includes a shallow trench isolation and an active structure defined by the shallow trench isolation and the active structure includes a first active area and a second active area. The first active area includes a plurality of active area units being parallel extended along a first direction, and the second active area is disposed outside a periphery of the first active area, to surround all of the active area units. The word lines are disposed in the substrate to intersect the active area units and the shallow trench isolation. The word lines includes first word lines arranged by a first pitch and second word lines arranged by a second pitch, and the second pitch is greater than the first pitch.