Source/Drain Contact Layout Under Power Rail to Prevent Shorting
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Solution Overview
Problem
In semiconductor device manufacturing, the challenge is to accurately position source/drain contacts without causing contact shorting, especially as feature sizes shrink and alignment errors become more critical, particularly when connecting to power rail vias.
Innovation Solution
A semiconductor structure is developed with a gate cut region lined with a dielectric core, allowing for self-alignment and insulation during the formation of source/drain contacts, which includes a liner and a dielectric core that helps in accurately positioning the contacts to prevent shorting by selectively etching the dielectric core and forming contacts that overlap the liner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If source/drain contacts are positioned closer together to reduce device area, then area efficiency is improved, but contact shorting risk increases
Solution Approach 1:
A dielectric core is introduced as an intermediary material between adjacent source/drain contacts. This dielectric core extends laterally between the contacts and vertically through the interlayer dielectric, creating a physical barrier that prevents electrical shorting while allowing the contacts to be positioned closer together, thus reducing device area without compromising reliability.
2Productivity
If feature sizes are reduced to increase device density, then device density is improved, but alignment precision requirements increase
Solution Approach 1:
The dielectric core is formed in advance before the source/drain contact patterning step. By pre-forming the dielectric core structure that extends laterally between contact regions, the subsequent contact alignment becomes more tolerant to manufacturing variations, as the dielectric core provides a built-in guide and barrier structure that compensates for alignment tolerances.
3Manufacturing precision
If self-alignment structures are added to improve contact positioning, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The dielectric core serves multiple functions simultaneously: it provides electrical insulation between adjacent contacts, acts as a self-alignment reference for contact patterning, and extends laterally to prevent contact encroachment. By combining these multiple functions into a single structural element, the solution improves contact positioning accuracy without proportionally increasing device complexity.
Data Source
AI summary
Embodiments disclosed herein include a semiconductor structure for reducing contact to contact shorting. The semiconductor structure may include a gate cut region with a liner and a dielectric core confined within a first lateral side of the liner and a second lateral side of the liner. The semiconductor structure may also include a first source/drain (S/D) contact overlapping the first lateral side and the dielectric core. The first S/D may include a line-end that contacts the second lateral side of the liner.