Semiconductor Isolation Structure for Active Region Corner Protection
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Solution Overview
Problem
The existing shallow trench isolation technology in semiconductor manufacturing faces challenges in reducing feature size and improving device performance, particularly due to issues with corner region protection during plasma etching, which affects the stability and uniformity of the active region and gate oxide layer.
Innovation Solution
A method involving a plasma etching process to form initial trenches and a first protective layer on the corner region using a reactive gas with high oxygen concentration, followed by a third etching process to form the active region, and a second protective layer on the trench sides, using an in situ steam generation process to minimize etching damage and maintain uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shallow trench isolation technology is used to reduce feature size, then manufacturing precision is improved, but corner region protection is insufficient leading to active region instability
Solution Approach 1:
A first protective layer is formed on the corner region before the main etching process. This preliminary protective layer prevents excessive etching of the corner region during subsequent plasma etching processes, thereby maintaining active region stability while enabling precise feature size reduction through shallow trench isolation technology.
Solution Approach 2:
The protective layer is selectively applied to the corner region rather than uniformly across the entire substrate. This localized protection strategy addresses the specific vulnerability of corner regions to over-etching while preserving the effectiveness of shallow trench isolation in reducing feature size elsewhere.
2Productivity
If plasma etching is performed to form trenches, then productivity is improved, but corner region over-etching occurs reducing manufacturing precision
Solution Approach 1:
The first protective layer is applied to the corner region before plasma etching to counteract the harmful effect of over-etching. This preliminary protective measure allows aggressive plasma etching parameters to be used for high productivity while the protective layer prevents corner region dimensions from deteriorating.
Solution Approach 2:
The protective layer acts as an intermediary between the plasma etching process and the corner region. It mediates the interaction by absorbing the excessive etching action, thereby protecting the corner region dimensions while allowing the plasma etching process to proceed at high speed for improved productivity.
3Stability of the object's composition
If first protective layer is formed on corner region, then active region stability is improved, but device complexity increases
Solution Approach 1:
The protective layer is selectively applied only to the corner region rather than the entire substrate. This localized approach improves active region stability where needed while minimizing the increase in device complexity by limiting the additional process steps to specific critical areas.
Solution Approach 2:
The protective layer formation is integrated into the existing process flow as a preliminary step before main etching. By positioning this stability-enhancing step early in the process sequence, the patent improves active region stability while avoiding the need for additional complex post-processing steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the size stability of the active region, reduces further etching of the corner region, and maintains the uniformity of the gate oxide layer, thereby improving device performance and stability.
Implementation Method 1
a plasma etching process is performed to form a plurality of trenches and an active region between the plurality of trenches
Implementation Method 2
a reaction gas is introduced into an etching cavity to form a first protective layer on a surface of the corner region
Implementation Method 3
using an in situ steam generation process to minimize etching damage
Data Source
AI summary
The present disclosure provides a semiconductor structure and a method for forming the semiconductor structure. The method includes: providing a substrate; forming a mask layer on the substrate, wherein the mask layer exposes a part of a surface of the substrate; etching the substrate by a plasma etching process using the mask layer as a mask to form a plurality of trenches and an active region between the plurality of trenches; and forming an insulating layer in the plurality of trenches. The method according to some embodiments of the present disclosure can protect a corner region of the active region and improve a size stability of the active region.