FinFET Source/Drain Contact Isolation for Dense IC Wiring
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Solution Overview
Problem
As integrated circuit devices are downscaled, there is a need for a stable and optimized wiring structure that maintains accuracy and high operation speeds in a reduced area, which existing technologies struggle to achieve due to issues with device isolation and contact formation.
Innovation Solution
The integration of fin-type active regions with source/drain regions, device isolation films, and contact isolation insulating films, where the contact isolation insulating films have a lower surface closer to the substrate than the source/drain contacts, and via power rails connected to the source/drain contacts, stabilizing the electrical connection and reliability even in reduced device areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the device area is reduced due to down-scaling, then the integration density is improved, but the reliability of electrical connections deteriorates
Solution Approach 1:
The contact isolation insulating film extends in the vertical dimension below the source/drain contacts, creating a three-dimensional isolation structure. This vertical extension provides electrical isolation without occupying additional horizontal area, thus maintaining high integration density while ensuring connection reliability through proper isolation of adjacent contacts.
Solution Approach 2:
The contact isolation insulating film acts as an intermediary element between adjacent source/drain contacts. By positioning this insulating film to extend below the contacts, it mediates the electrical isolation between neighboring contacts, preventing unwanted current paths while maintaining the compact device footprint.
2Area of moving object
If the device area is reduced due to down-scaling, then the integration density is improved, but the stability of wiring structure deteriorates
Solution Approach 1:
The wiring stability is enhanced by extending the contact isolation insulating film vertically below the source/drain contacts. This creates a more robust three-dimensional wiring architecture that provides stable electrical connections without requiring increased horizontal spacing, thus maintaining compact device area while improving structural stability.
3Reliability
If contact isolation is improved by adding isolation structures, then the electrical connection reliability is improved, but the device complexity increases
Solution Approach 1:
The contact isolation insulating film serves multiple functions simultaneously: it provides electrical isolation between adjacent source/drain contacts, defines the contact region boundaries, and contributes to the overall device structural integrity. This multi-functionality improves electrical connection reliability without proportionally increasing device complexity.
Solution Approach 2:
The contact isolation function is merged with the existing contact formation process by integrating the isolation insulating film formation into the same fabrication sequence as the source/drain contact creation. This combines multiple functions into a unified structure, improving electrical isolation while minimizing the increase in overall device complexity.
Data Source
AI summary
An integrated circuit device includes fin-type active regions protruding from a substrate and extending lengthwise in a first horizontal direction, source/drain regions respectively arranged on the fin-type active regions, a device isolation film covering both sidewalls of each fin-type active region, an insulating structure covering the source/drain regions and the device isolation film, source/drain contacts respectively arranged on and connected to the source/drain regions and apart from each other in a second horizontal direction perpendicular to the first horizontal direction, and a contact isolation insulating film arranged between the source/drain contacts in the second horizontal direction and having a lower surface closer to the substrate than a lower surface of each source/drain contact. At least one of the source/drain contacts includes a first portion extending in a vertical direction toward the substrate along a surface of the contact isolation insulating film.