Well Contact Diffusion Region Resistance Reduction via 3D Stacked Contacts
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Solution Overview
Problem
In semiconductor devices, the high resistance of well contact diffusion regions relative to power lines necessitates a shorter pitch for contact plugs connecting them, which can be challenging to achieve effectively.
Innovation Solution
The configuration of contact plugs and wiring patterns is optimized to reduce resistance by extending in the x-direction and using multiple layers of interlayer dielectric films, allowing for a shorter array pitch of contact plugs while maintaining effective connectivity between well contact diffusion regions and power lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact plugs are arrayed at a shorter pitch to reduce resistance in well contact diffusion regions, then the resistance of well potential supply paths is reduced, but the manufacturing complexity and difficulty of achieving the shorter pitch increase
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of contact plugs to a three-dimensional stacked configuration where contact plugs are arranged in multiple layers (first and second contact plug arrays at different heights). This vertical dimensionality change allows achieving shorter effective pitch and lower resistance without the manufacturing difficulties associated with tightly spaced planar contacts, as the contacts can be formed in separate processing steps at different elevations.
Solution Approach 2:
The patent divides the single contact plug function into multiple segmented contact plugs arranged in arrays (first contact plug array and second contact plug array). Each contact plug in the array contributes to the overall current path, effectively segmenting the current flow across multiple parallel paths. This segmentation reduces the resistance of the well potential supply path while distributing the manufacturing complexity across multiple simpler, identical structures rather than requiring a single complex high-density contact arrangement.
2Reliability
If multiple layers of interlayer dielectric films are used to enable shorter contact plug pitch, then connectivity between well contact diffusion regions and power lines is improved, but the device complexity increases
Solution Approach 1:
The patent utilizes the vertical dimension by stacking multiple interlayer dielectric films and contact plug arrays at different heights (first interlayer dielectric film with first contact plug array, second interlayer dielectric film with second contact plug array). This three-dimensional wiring structure improves connectivity and reduces resistance by providing multiple parallel current paths through different vertical layers, while the modular layered architecture manages complexity through systematic repetition of similar structural units rather than arbitrary complex routing.
Data Source
AI summary
Disclosed herein is an apparatus that includes: a first diffusion region extending in a first direction; second diffusion regions arranged in the first direction; a first metallic line overlapping with the first diffusion region; second metallic lines each overlapping with an associated one of the second diffusion regions; a third metallic line overlapping with the first and second metallic lines; first contact plugs connecting the first metallic line to the first diffusion region; second contact plugs each electrically connecting an associated one of the second metallic lines to an associated one of the second diffusion regions; and third contact plugs each electrically connecting the third metallic line to an associated one of the second metallic lines.