Selective Corner Deposition to Prevent SiN Etch Loss
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Solution Overview
Problem
The ongoing miniaturization of semiconductor devices poses challenges in maintaining structural integrity during fabrication, particularly due to corner loss, pinch-off, and related defects in silicon nitride (SiN) layers used as spacers or protective caps, which can compromise device functionality and reduce fabrication yields.
Innovation Solution
The methods involve performing a first etching process to selectively expose corner portions of a first material layer within a multi-layered semiconductor structure, followed by a surface treatment and selective deposition of a protective material onto the functionalized corner portions, facilitated by chemical selectivity, surface reactivity, or steric hindrance associated with the surface-modifying agent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If aggressive etching steps are used to define fine features, then manufacturing precision is improved, but corner loss and structural integrity deteriorate
Solution Approach 1:
A protective material is deposited on the silicon nitride layer before the aggressive etching step. This preliminary protective layer prevents corner loss and structural degradation during the etching process, allowing the use of aggressive etching conditions to achieve fine feature definition without compromising structural integrity.
Solution Approach 2:
The protective material acts as an intermediary layer between the aggressive etching plasma and the silicon nitride structure. This intermediary layer absorbs the harmful effects of the aggressive etchant, enabling precise feature definition while protecting the underlying structure from corner loss and pinch-off defects.
2Reliability
If atomic layer etching (ALE) is used to address corner loss, then structural integrity is improved, but productivity decreases
Solution Approach 1:
Instead of using slow ALE processes, a protective material is deposited beforehand to prevent corner loss during subsequent etching steps. This approach maintains structural integrity while allowing the use of faster, more productive etching methods, thereby avoiding the throughput penalty associated with ALE.
3Reliability
If the thickness of SiN layers is increased to prevent corner loss, then structural integrity is improved, but device topography and aspect ratios deteriorate
Solution Approach 1:
A protective material is deposited on the silicon nitride layer before etching to prevent corner loss. This allows the use of thinner SiN layers that maintain appropriate device topography and aspect ratios, while still achieving sufficient structural integrity through the protective layer during the etching process.
4Reliability
If protective material is selectively deposited on corner portions, then corner loss is mitigated, but process complexity increases
Solution Approach 1:
The protective material is selectively deposited only on the corner portions of the silicon nitride layer using area-selective deposition techniques. This localized approach provides targeted protection where it is most needed to prevent corner loss, while minimizing the overall process complexity and avoiding the need for complex masking or patterning 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 effectively mitigates etch-induced degradation and structural impacts on the corner portions, enhancing precision and reliability in semiconductor device fabrication by reducing material damage and process variability.
Implementation Method 1
functionalization with a surface-modifying agent to enable selective deposition
Implementation Method 2
A protective material can be selectively deposited onto the functionalized corner portions of the first material layer
Implementation Method 3
facilitated by chemical selectivity, surface reactivity, or steric hindrance associated with the surface-modifying agent
Data Source
AI summary
Some aspects of the inventive concepts relate to methods for mitigating corner loss in semiconductor fabrication. The methods can include performing a first etching process to selectively expose corner portions of a first material layer within a multi-layered semiconductor structure by removing portions of a second material layer adjacent to the first material layer. The exposed corner portions can undergo a surface treatment comprising a pretreatment process to modify chemical or physical properties and functionalization with a surface-modifying agent to enable selective deposition. A protective material can be selectively deposited onto the corner portions of the first material layer. In some aspects, a second etching process can be performed to remove additional portions of the multi-layered structure, with the protective material mitigating etch-induced degradation or structural impacts on the corner portions, thereby enhancing precision and reliability in semiconductor device fabrication.