Oblique Contact Pad for 6F2 Semiconductor Active Region Margin
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Solution Overview
Problem
The conventional 6F2 semiconductor device architecture faces challenges in securing a sufficient process margin for storage node contact plugs due to limited exposed area at the edges of active regions, leading to potential bridges between active regions and increased production costs when attempting to increase the critical dimension of active regions.
Innovation Solution
The semiconductor device incorporates a contact pad that extends in the oblique direction to expand the active region's critical dimension, preventing bridges between active regions and enhancing the contact margin of storage node contact plugs without altering the design of existing components like buried gates and bit lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the longitudinal length of the active region is increased to secure contact margin, then the contact margin is improved, but bridges may be formed between adjacent active regions
Solution Approach 1:
The patent introduces a contact pad structure that extends in the longitudinal direction of the active region, effectively adding a dimensional element to expand the contact area without increasing the active region's longitudinal length. This allows the storage node contact plug to achieve sufficient contact margin while maintaining safe spacing between adjacent active regions to prevent bridges.
Solution Approach 2:
The patent segments the contact structure by introducing a separate contact pad component that is distinct from the active region itself. The contact pad is formed through selective etching and filling processes, creating an independent conductive element that extends along the active region to provide enhanced contact area without modifying the active region geometry.
2Reliability
If the design of active region is changed to prevent bridges, then bridge formation is prevented, but the design of all subsequent components must be changed increasing production cost
Solution Approach 1:
The patent applies local quality by introducing the contact pad structure only at specific locations where contact is needed, rather than changing the overall active region design. The contact pad extends locally in the longitudinal direction to provide enhanced contact area, while the rest of the device architecture including buried gates and bit lines remains unchanged, thus avoiding increased production costs.
3Manufacturing precision
If the active region critical dimension is increased to secure contact margin, then the contact margin is improved, but the area available for other components is reduced
Solution Approach 1:
The patent utilizes the longitudinal dimension of the active region by extending the contact pad in this direction, rather than increasing the critical dimension (width) of the active region. This dimensional approach allows the contact margin to be improved while preserving the active region's cross-sectional area, leaving sufficient space for buried gates, bit lines, and other device components.
Data Source
AI summary
A semiconductor device includes a word line, a bit line crossing the word line, an active region arranged in an oblique direction at the word line and the bit line, and a contact pad contacting the active region, where the contact pad extends in the oblique direction.