Source/Drain Contact Recess Layout Near Rail Patterns
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Solution Overview
Problem
The increasing complexity and integration of semiconductor devices demand improved performance, reliability, and yield, which existing technologies struggle to meet due to challenges in the design and fabrication of advanced semiconductor structures.
Innovation Solution
The semiconductor device incorporates an active pattern on a substrate with a gate structure intersecting it, along with source/drain contacts, via patterns, rail patterns, and wiring patterns. The source/drain contacts feature recesses that are recessed more downwardly than their upper surfaces, and these recesses are adjacent to the rail patterns, enhancing the device's performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If source/drain contacts are made larger to reduce electrical resistance, then conductivity improves, but device area increases and integration density decreases
Solution Approach 1:
The patent introduces a vertical recess structure in the source/drain contact, transitioning from a planar contact geometry to a three-dimensional structure. The recess extends downward into the source/drain region, increasing the effective contact area in the vertical dimension while maintaining a compact footprint in the horizontal plane, thus reducing electrical resistance without increasing device area
Solution Approach 2:
The recess structure is nested within the source/drain contact region, with the contact material extending downward into the source/drain region. This nested configuration allows the contact to access additional conductive pathways within the vertical profile of the source/drain region, effectively increasing conductivity without occupying additional lateral space
2Reliability
If source/drain contacts are made larger to improve conductivity, then electrical resistance decreases, but proximity to rail patterns increases causing short circuit risks
Solution Approach 1:
By extending the contact vertically into a recess rather than expanding horizontally, the design achieves increased conductivity through enhanced vertical contact area while maintaining safe horizontal spacing from adjacent rail patterns, thereby eliminating the short circuit risk associated with lateral expansion
Solution Approach 2:
The recess is strategically positioned and sized to provide sufficient contact area for low resistance while maintaining appropriate clearance from rail patterns. The local geometry is optimized to achieve the desired electrical performance without compromising electrical isolation from adjacent structures
3Reliability
If device structures are made more complex to improve performance, then device performance improves, but manufacturing precision requirements increase
Solution Approach 1:
The recess structure is formed as an integrated part of the source/drain contact fabrication process, using the same etching and filling steps that define the contact geometry. By establishing the recess profile during the primary contact formation process rather than adding it as a separate subsequent step, the design achieves complex three-dimensional geometry without proportionally increasing manufacturing precision requirements
Data Source
AI summary
A semiconductor device includes: an active pattern extending in a first direction across an underlying substrate, a gate structure extending in a second direction, on the active pattern, a first source/drain contact electrically connected to a source/drain region within the active pattern, on one side of the gate structure, and a first via pattern electrically connected to an upper surface of the first source/drain contact. A rail pattern is provided, which extends in the first direction, and is spaced apart from the first via pattern in the second direction. A wiring pattern extends in the first direction, and is electrically connected to an upper surface of the rail pattern. The first source/drain contact includes a first recess therein, which is more recessed downwardly relative to the upper surface of the first source/drain contact, and at least a portion of the first recess extends adjacent to the rail pattern.