Gate Electrode Height Segmentation for Short-Free SAC Contacts
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Solution Overview
Problem
Current semiconductor device fabrication methods face challenges in preventing short circuits between the gate electrode and source/drain region due to insufficient height differences in self-aligned contact processes, leading to reliability and integration issues.
Innovation Solution
The semiconductor device incorporates a gate electrode with distinct height portions, where the first portion has a lower top surface and the second portion has a higher top surface, allowing for a sufficient distance between contact plugs and the source/drain regions, preventing short circuits and enhancing product reliability and process margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a self-aligned contact process is used with insufficient height difference between gate electrode and source/drain region, then the fabrication process is simplified, but short circuits occur between contact plugs and source/drain regions
Solution Approach 1:
The gate electrode is divided into two distinct portions: a first portion with a lower top surface and a second portion with a higher top surface. This segmentation creates different height levels that enable the self-aligned contact process to work effectively by providing sufficient height difference between the gate electrode and source/drain region, thus preventing short circuits while maintaining process simplicity.
Solution Approach 2:
Different portions of the gate electrode are given different local qualities in terms of height. The first portion has a lower top surface while the second portion has a higher top surface. This local quality variation allows the contact plugs to be properly aligned and positioned without causing short circuits to the source/drain regions, resolving the contradiction between process simplicity and reliability.
2Reliability
If the gate electrode is formed with distinct height portions, then short circuit prevention is improved, but the device structure becomes more complex
Solution Approach 1:
The gate electrode is segmented into two portions with different heights, where the first portion has a lower top surface and the second portion has a higher top surface. This segmentation provides the necessary height difference for reliable self-aligned contact formation while maintaining a relatively simple overall structure that can be integrated into existing semiconductor devices.
Solution Approach 2:
The height parameter of the gate electrode is varied across different portions. By changing the height parameter locally (lower for the first portion, higher for the second portion), the design achieves improved short circuit prevention without requiring fundamentally new structures, thus limiting the increase in device complexity.
3Manufacturing precision
If contact plugs are positioned closer to source/drain regions, then manufacturing precision requirements are reduced, but short circuits occur
Solution Approach 1:
The gate electrode structure creates an equipotential-like height difference between the first portion (lower top surface) and the second portion (higher top surface). This height differentiation establishes a natural barrier that prevents contact plugs from shorting to the source/drain regions, allowing for relaxed alignment tolerances while maintaining reliability.
Solution Approach 2:
The gate electrode exhibits different local qualities in terms of height at different positions. The first portion has a lower top surface while the second portion has a higher top surface, creating local height variations that provide sufficient clearance for contact plugs without requiring extremely precise manufacturing, thus reducing precision requirements while preventing short circuits.
Data Source
AI summary
A semiconductor device includes an active pattern on a substrate, the active pattern extending in a first direction, a gate electrode on the active pattern, the gate electrode extending in a second direction intersecting the first direction and including a first portion and a second portion arranged along the second direction, a first contact plug on the gate electrode, the first contact plug being connected to a top surface of the second portion of the gate electrode, a source/drain region in the active pattern on a sidewall of the gate electrode, and a source/drain contact on the source/drain region, a height of a top surface of the source/drain contact being higher than a top surface of the first portion of the gate electrode and lower than the top surface of the second portion of the gate electrode.