Scaled Gate Contact With U-Shape Dielectric For Short Prevention
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Solution Overview
Problem
In semiconductor structures, the scaling of gate contacts over active regions poses a challenge as it increases the risk of shorts between the gate contact and metal plugs, necessitating a solution that maintains electrical integrity while minimizing this risk.
Innovation Solution
A self-aligned scaled gate contact is formed directly over the active region with a U-shape dielectric material around it, and source/drain contacts are recessed to isolate the gate contact, reducing resistance and avoiding shorts through a method involving multiple fabrication steps including deposition, patterning, and etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gate contact is formed directly above the active region (CB-over-active), then the device size is reduced and scaling is improved, but the risk of short between gate contact and metal plugs increases
Solution Approach 1:
A dielectric material is introduced as an intermediary between the gate contact and the metal plugs. This dielectric layer is positioned to electrically isolate the gate contact from adjacent metal plugs while allowing the gate contact to extend directly over the active region, thus enabling scaling without increasing short risk
Solution Approach 2:
The gate contact structure is segmented into distinct regions: a first portion extending over the active region and a second portion extending over the isolation region. This segmentation allows the gate contact to be positioned optimally for scaling while maintaining electrical isolation from metal plugs through the dielectric material
2Reliability
If the gate contact is offset from the active region to avoid shorts, then electrical integrity is maintained, but device size increases and scaling is hindered
Solution Approach 1:
The dielectric material serves as a mediator that allows the gate contact to be positioned directly over the active region while maintaining electrical integrity. The dielectric provides the necessary isolation from metal plugs, eliminating the need to offset the gate contact for short prevention
3Productivity
If the source/drain contact cap area is reduced for scaling, then device size is minimized, but the minimum area requirement for proper function is compromised
Solution Approach 1:
The source/drain contact cap is designed with non-uniform dimensions: a first dimension extending in a first direction and a second dimension extending in a second direction perpendicular to the first. This local quality variation allows the cap to meet minimum area requirements in critical directions while minimizing overall footprint for scaling
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to a scaled gate contact and source/drain cap and methods of manufacture. The structure includes: a gate structure comprising an active region; source and drain contacts adjacent to the gate structure; a capping material over the source and drain contacts; a gate contact formed directly above the active region of the gate structure and over the capping material; a U-shape dielectric material around the gate contact, above the source and drain contacts; and a contact in direct electrical contact to the source and drain contacts.