FinFET Source/Drain Contact Layout With Lateral Barrier Expansion
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Solution Overview
Problem
The challenge in integrated circuit devices is to reduce the area occupied by wirings and contacts, ensure reliable electrical isolation between them, and enhance the reliability and speed of operations as devices scale down.
Innovation Solution
The integrated circuit devices incorporate a fin-type active region with a specific structure that includes a gate line, source/drain regions, an interlayer insulating film, and a conductive barrier film with a lateral expansion portion and through portion in the source/drain contact hole, where the conductive barrier film's topmost surface is closer to the substrate than the metal plug, enhancing electrical isolation and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the device region is reduced by down-scaling, then the area occupied by wirings and contacts is reduced, but the reliability and electrical isolation between wirings and contacts deteriorates
Solution Approach 1:
The conductive barrier film is configured with a lateral expansion portion that protrudes laterally from the source/drain contact hole, utilizing the horizontal dimension to enhance electrical isolation. This lateral expansion provides an additional isolation barrier without increasing the vertical height of the contact structure, thus reducing the area occupied while maintaining reliability.
Solution Approach 2:
The conductive barrier film acts as an intermediary structure between the metal plug and the surrounding insulating film. The lateral expansion portion of the conductive barrier film creates an extended isolation barrier that mediates the electrical isolation requirement, allowing smaller contact dimensions while maintaining reliable electrical isolation between adjacent wirings and contacts.
2Speed
If the device region is reduced by down-scaling, then the operating speed may be improved, but the reliability of operations deteriorates
Solution Approach 1:
The lateral expansion portion extends the conductive barrier film horizontally beyond the vertical walls of the source/drain contact hole. This dimensional extension provides enhanced electrical isolation and reliability without increasing the vertical profile, enabling faster operation at reduced device dimensions while maintaining operational reliability.
Solution Approach 2:
The conductive barrier film with lateral expansion is formed in advance during the contact hole formation process, creating a pre-established isolation structure. This preliminary configuration ensures that electrical isolation and reliability are secured before subsequent wiring formation, allowing for faster processing and operation while maintaining reliability in scaled-down devices.
Data Source
AI summary
Integrated circuit devices may include a fin-type active region, a gate line extending on the fin-type active region, a source/drain region on the fin-type active region and adjacent to the gate line, an interlayer insulating film covering the source/drain region, a source/drain contact hole penetrating the interlayer insulating film toward the source/drain region, a metal plug in the source/drain contact hole, and a conductive barrier film covering a sidewall of the metal plug in the source/drain contact hole. The metal plug includes a lateral expansion portion and a through portion vertically extending from the lateral expansion portion toward the source/drain region. A width of the lateral expansion is greater than a width of the through portion, and a topmost surface of the conductive barrier film is closer than a topmost surface of the metal plug to the substrate.