Dielectric Recess Capping to Block Etchant Penetration
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Solution Overview
Problem
Existing semiconductor manufacturing methods face challenges in effectively embedding films in recesses of substrates while preventing damage to underlying structures during etching processes, particularly due to non-uniform portions in dielectric films.
Innovation Solution
A substrate processing method involving the formation of a dielectric film with a non-uniform portion in a concavo-convex structure, followed by exposing it to oxygen plasma to form a protective cap layer that seals these non-uniformities, thereby preventing etchant penetration and protecting underlying layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric film is formed on a concavo-convex structure to embed a film in a recess, then the film embedding is achieved, but non-uniform portions remain in the recess that can allow etchant penetration and cause damage to underlying structures
Solution Approach 1:
A cap layer is formed on the dielectric film before the etching process to seal non-uniform portions and prevent etchant penetration. This preliminary protective action ensures that even if the dielectric film has non-uniformities, the underlying source and drain layers are protected from damage during subsequent etching operations.
Solution Approach 2:
The cap layer acts as an intermediary protective layer between the dielectric film and the etchant. It seals the non-uniform portions of the dielectric film and prevents direct contact between the etchant and the underlying source and drain layers, thereby protecting them from damage while allowing the etching process to proceed.
2Device complexity
If the dielectric film is made thinner to reduce processing steps, then manufacturing complexity is reduced, but etchant can more easily penetrate through non-uniform portions and damage underlying layers
Solution Approach 1:
The cap layer is formed as an additional protective layer before etching, providing a seal over non-uniform portions of the dielectric film. This preliminary protection compensates for the reduced thickness of the dielectric film, ensuring that etchant penetration is prevented even when the dielectric film is thin, thus maintaining reliability without adding significant processing complexity.
3Reliability
If a thicker dielectric film is used to prevent etchant penetration, then protection of underlying layers is improved, but the processing time and manufacturing complexity increase
Solution Approach 1:
Instead of increasing dielectric film thickness, a cap layer is formed as a preliminary protective measure. This cap layer provides the necessary protection against etchant penetration with minimal additional processing time, avoiding the time-consuming requirement of depositing a thicker dielectric film while maintaining the same level of protection for underlying layers.
Solution Approach 2:
The solution changes the protective approach from increasing dielectric film thickness to adding a separate cap layer. This parameter change allows for effective protection with reduced processing time, as the cap layer can be formed more efficiently than increasing the thickness of the main dielectric film.
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
The method ensures the integrity of source and drain layers by sealing non-uniform portions, reducing damage during etching and enhancing the reliability of semiconductor devices.
Implementation Method 1
forming a protective film on a surface of the dielectric film by exposing the dielectric film to first plasma including an oxygen gas
Implementation Method 2
exposing the dielectric film to first plasma including an oxygen gas, to form the protective film including a cap layer
Data Source
AI summary
A substrate processing method includes the processes of preparing a substrate having a concave-convex structure, forming a dielectric film including at least silicon and nitrogen on the concavo-convex structure, to form the dielectric film having a non-uniform portion in a recess of the concavo-convex structure, and forming a protective film on a surface of the dielectric film by exposing the dielectric film to first plasma including an oxygen gas, to form the protective film including a cap layer that closes the non-uniform portion by bonding an upper side of the non-uniform portion of the concavo-convex structure.