Semiconductor Trench Isolation for Complete Silicification
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Solution Overview
Problem
The semiconductor structure has a low yield due to difficulties in forming buried bit lines (BLs) caused by the incomplete removal of a thick first insulating layer on the sidewall of trenches, which hinders the silicification process and results in inadequate exposure of the substrate for further processing.
Innovation Solution
A method involving the sequential formation of a first and second insulating layer on the sidewall of a trench, where the first insulating layer is thinner than the target value, allowing for a larger substrate exposure for silicification, followed by the formation of a second insulating layer that, together with the first, achieves the target thickness, enabling effective manufacturing of word lines and improving the semiconductor structure's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a first insulating layer is formed on the sidewall of the first trench, then the silicification reaction can be performed on the exposed substrate, but the first insulating layer cannot be completely removed from the bottom of the first trench, leading to incomplete silicification
Solution Approach 1:
The insulating layer formation process is segmented into two distinct stages: first forming a thin first insulating layer to enable substrate exposure and silicification, then forming a second insulating layer to achieve the target thickness. This segmentation allows the first insulating layer to be partially removed during silicification while the second layer remains to provide adequate thickness, resolving the contradiction between complete silicification and ease of manufacture.
Solution Approach 2:
The silicification reaction is performed as a preliminary action before forming the second insulating layer. By conducting silicification when only the thin first insulating layer is present, the substrate is fully exposed and can undergo complete silicification. The second insulating layer is then formed afterward to achieve the required thickness, eliminating the removal difficulty while ensuring complete silicification.
2Reliability
If the first insulating layer thickness is increased to ensure adequate space for word lines, then the yield improves, but the substrate exposure area decreases, leading to incomplete silicification
Solution Approach 1:
The insulating layer formation is divided into two segments: a thin first insulating layer that allows complete substrate exposure and silicification, followed by a second insulating layer that provides the additional thickness needed for adequate word line spacing. This segmentation resolves the contradiction by achieving both complete silicification and sufficient total thickness.
Solution Approach 2:
Silicification is performed as a preliminary step before forming the second insulating layer. The thin first insulating layer enables complete substrate exposure during this preliminary silicification action. After silicification is complete, the second insulating layer is formed to provide the necessary thickness for reliable word line formation and high yield.
3Manufacturing precision
If the first insulating layer is made thinner to enable complete silicification, then the substrate can be fully silicified, but the space for forming word lines becomes insufficient
Solution Approach 1:
The insulating layer is segmented into two functional parts: the first insulating layer (thin) that enables complete substrate exposure for silicification, and the second insulating layer (thicker) that provides the necessary space for word line formation. Together they achieve both complete silicification and adequate device formation space.
Solution Approach 2:
The silicification reaction is performed as a preliminary action while only the thin first insulating layer is present, ensuring complete substrate exposure and thorough silicification. After this preliminary silicification step, the second insulating layer is formed to provide the required space for word line formation, eliminating the space constraint.
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 yield of the semiconductor structure by ensuring a sufficient space for word line formation and improving the integration of the silicified substrate, leading to better performance and manufacturing efficiency.
Implementation Method 1
performing a silicification reaction on a substrate exposed in the second trench
Data Source
AI summary
The present disclosure provides a semiconductor structure and a manufacturing method thereof, relates to the technical field of semiconductors. The manufacturing method includes: forming a plurality of first trenches arranged at intervals and extending along a first direction in a base; forming a first insulating layer on a sidewall of the first trench, where a thickness of the first insulating layer is smaller than a target value, and the first insulating layer defines a second trench; performing a silicification reaction on a substrate exposed in the second trench; forming a second insulating layer on a sidewall of the second trench, where the second insulating layer defines a third trench, and a sum of thicknesses of the first insulating layer and the second insulating layer is equal to the target value; and forming an isolation layer in the third trench.