Semiconductor Contact Holes Near Gates Using Protection Umbrella
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Solution Overview
Problem
In the fabrication of semiconductor FETs, there is a challenge in forming source/drain contact holes close to the gate while ensuring electrical insulation, which is crucial for increasing device density without compromising performance.
Innovation Solution
The method involves creating a protection umbrella region using a hard cap layer to shield the gate region from contact holes, allowing for the blanket deposition of an inter-level dielectric layer and the subsequent formation of contact holes directly above the source/drain regions, which are aligned with the edge of the umbrella region and isolated from the gate, ensuring electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If contact holes are formed close to the gate to increase device density, then device density is improved, but electrical insulation between the contact holes and gate is compromised
Solution Approach 1:
A protection umbrella region is introduced as an intermediary structure between the gate and the contact holes. This umbrella-shaped protective layer extends laterally from the gate, creating a physical barrier that prevents direct contact and ensures electrical insulation while allowing the contact holes to be positioned close to the gate for high device density.
Solution Approach 2:
The protection umbrella region extends in the lateral dimension from the gate structure, creating a three-dimensional protective barrier. This dimensional extension allows the contact holes to be positioned close to the gate in the planar view while maintaining vertical separation and electrical insulation through the laterally extending umbrella structure.
2Productivity
If contact holes are formed close to the gate, then device density is improved, but manufacturing complexity increases due to the need for precise alignment and isolation structures
Solution Approach 1:
The protection umbrella region is formed in advance before the contact holes are created. This preliminary formation of the protective barrier simplifies subsequent processing steps, as the umbrella structure is already in place to guide contact hole positioning and ensure proper isolation, reducing the need for complex alignment procedures.
Solution Approach 2:
The protection umbrella region serves multiple functions simultaneously: it provides electrical insulation between the gate and contact holes, acts as a positioning reference for contact hole alignment, and serves as a protective barrier during subsequent processing steps. This multi-functionality reduces the need for separate structures for each purpose.
Data Source
AI summary
A semiconductor structure. The structure includes (a) a semiconductor layer including a channel region disposed between first and second S/D regions; (b) a gate dielectric region on the channel region; (c) a gate region on the gate dielectric region and electrically insulated from the channel region by the gate dielectric region; (d) a protection umbrella region on the gate region, wherein the protection umbrella region comprises a first dielectric material, and wherein the gate region is completely in a shadow of the protection umbrella region; and (e) a filled contact hole (i) directly above and electrically connected to the second S/D region and (ii) aligned with an edge of the protection umbrella region, wherein the contact hole is physically isolated from the gate region by an inter-level dielectric (ILD) layer which comprises a second dielectric material different from the first dielectric material.