Gate Contact Stepped Profile for Electrical Short Prevention
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Solution Overview
Problem
Semiconductor devices face challenges in achieving high reliability and complexity due to issues with electrical shorts and stress distribution in their structures, particularly in the integration of source/drain patterns and gate contacts.
Innovation Solution
The semiconductor device incorporates a gate contact design with a first portion vertically overlapping the gate electrode and a second portion laterally extending to overlap with the device isolation layer, preventing electrical shorts by maintaining a stepped profile that ensures the second portion is not in contact with adjacent source/drain patterns, thus improving stress distribution and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate contact is designed with a second portion laterally extending to overlap with the device isolation layer, then electrical shorts are prevented and reliability is improved, but the device structure becomes more complex
Solution Approach 1:
The gate contact is divided into two distinct portions: a first portion vertically overlapping with the gate electrode and a second portion laterally extending from the first portion to overlap with the device isolation layer. This segmentation allows each portion to serve a specific function - the first portion provides electrical connection while the second portion prevents electrical shorts by maintaining isolation, thus resolving the contradiction between reliability improvement and structural complexity.
2Reliability
If the bottom surface of the second portion is distal to the substrate in relation to the top of the source/drain pattern, then electrical shorts are prevented, but manufacturing precision requirements increase
Solution Approach 1:
The device isolation layer serves as an intermediary element between the gate contact and the source/drain pattern. The second portion of the gate contact overlaps with the device isolation layer rather than directly contacting the source/drain pattern, using the isolation layer as a mediator to prevent electrical shorts. This approach reduces manufacturing precision requirements compared to direct positioning control.
3Reliability
If the gate contact design optimizes stress distribution through the stepped profile, then device reliability is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The gate contact design introduces a vertical dimension variation through the stepped profile, where the bottom surface of the second portion is positioned at a different height relative to the substrate compared to the first portion. This dimensional change optimizes stress distribution by creating a gradual transition that reduces mechanical stress concentration, while the stepped structure can be integrated into existing manufacturing processes.
Data Source
AI summary
A semiconductor device includes a substrate including active patterns, a device isolation layer filling a trench between a pair of adjacent active patterns, a gate electrode on the active patterns, and a gate contact on the gate electrode. Each active pattern includes source/drain patterns at opposite sides of the gate electrode. The gate contact includes a first portion vertically overlapping with the gate electrode, and a second portion laterally extending from the first portion such that the second portion vertically overlaps with the device isolation layer and does not vertically overlap with the gate electrode. A bottom surface of the second portion is distal to the substrate in relation to a bottom surface of the first portion. The bottom surface of the second portion is distal to the substrate in relation to a top of a source/drain pattern that is adjacent to the second portion.