STI Trench Protective Layer for Wet Etch Isolation Reliability
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Solution Overview
Problem
Traditional Shallow Trench Isolation (STI) structures in semiconductor manufacturing are prone to excessive etching during wet etching processes, leading to defects and reduced performance and yield of semiconductor devices due to the use of oxide layers for insulation protection.
Innovation Solution
A manufacturing method for a semiconductor structure that involves forming a trench structure in a substrate, followed by a first dielectric layer with a top surface lower than the trench structure, and a protective layer that covers the dielectric layer and trench structure, preventing excessive etching and enhancing protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oxide layer is used for insulation protection in STI structure, then isolation performance is improved, but excessive etching occurs during wet etching processes leading to defects
Solution Approach 1:
A protective layer is introduced as an intermediary between the oxide layer and the wet etching process. This protective layer acts as a barrier that prevents the etching solution from directly contacting and excessively etching the oxide layer, while still allowing the isolation function to be maintained. The protective layer is selectively removed in subsequent processes to complete the STI structure formation.
2Reliability
If the top surface of the first dielectric layer is made lower than the top surface of the trench structure, then the protective layer can better cover and protect the dielectric layer surface, but the manufacturing process complexity increases
Solution Approach 1:
The first dielectric layer is formed with its top surface lower than the trench structure top surface before the protective layer is deposited. This preliminary action creates a recessed surface that allows the protective layer to fully cover and conform to the dielectric layer topology, ensuring complete protection without requiring additional complex processing steps later.
3Adaptability or versatility
If device sizes and isolation structure sizes are decreased to increase integration, then integration level is improved, but process complexities of isolation structures increase
Solution Approach 1:
The isolation structure is segmented into multiple functional layers: the oxide layer for insulation, the protective layer for etching protection, and the first dielectric layer for structural support. This segmentation allows each layer to be optimized independently for its specific function, enabling smaller device sizes and higher integration while managing process complexity through modular layer formation.
Data Source
AI summary
A semiconductor structure manufacturing method includes: a substrate is provided, and a trench structure is formed in the substrate; a first dielectric layer is formed in the trench structure, and a top surface of the first dielectric layer is lower than a top surface of the trench structure; and a protective layer is formed in the trench structure, and the protective layers at least covers a surface of the first dielectric layer and part of a side wall of the trench structure.