Flowable Film Densification to Prevent Void Formation in Features
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Solution Overview
Problem
Existing semiconductor processing methods face challenges in forming films with improved film quality, particularly in narrow features with high aspect ratios, where deposition on sidewalls can lead to pinching off and void formation.
Innovation Solution
A method involving the deposition of a flowable film on a substrate, followed by removing a portion of the film from the sidewalls using a dry etch process, and then reducing the hydrogen content of the remaining film to achieve a densified film. This process is controlled using plasma effluents of different precursors and includes a film treatment process to enhance film quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a flowable film is deposited on sidewalls of narrow features, then the film can conform to the feature geometry, but the sidewall coverage leads to pinching off and void formation
Solution Approach 1:
The patent removes the problematic sidewall coverage by performing a selective etch process that targets and removes the deposited film from sidewalls while preserving the film in the feature interior. This extraction of the harmful sidewall material prevents pinching off and void formation while maintaining the beneficial conformal deposition in the feature space.
Solution Approach 2:
The patent creates different film qualities in different locations: the film interior to features is densified and hydrogen-reduced for high quality, while sidewall coverage is selectively removed. This local differentiation allows the film to have optimal properties where needed (inside features) and minimal presence where harmful (on sidewalls).
2Manufacturing precision
If the flowable film is densified by reducing hydrogen content, then the film quality improves, but the process complexity increases with multiple precursor flows
Solution Approach 1:
The patent combines multiple functions into a single integrated process chamber that can perform deposition, selective etching, and hydrogen reduction/densification without requiring chamber transitions. This merging of deposition and treatment functions into one chamber simplifies the overall process architecture while achieving high film quality through controlled precursor flows.
Solution Approach 2:
The patent achieves film densification by dynamically changing process parameters - specifically switching between different precursor flows (silane for deposition, hydrogen-rich precursors for densification) and adjusting plasma conditions. These parameter changes enable transition from a flowable, hydrogen-rich film to a densified, high-quality film within the same chamber.
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 effectively addresses the challenges of film formation by achieving improved film quality, reducing sidewall coverage, and preventing voids within features, thereby enhancing device performance and processing efficiency.
Implementation Method 1
depositing a flowable film on a substrate by providing a first input flow, the first input flow including plasma effluents of a first precursor
Implementation Method 2
removing a portion of the flowable film from a sidewall of a feature defined within the substrate to obtain a remaining portion of the flowable film by providing a second input flow, the second input flow including plasma effluents of a second precursor
Implementation Method 3
reducing hydrogen content of the remaining portion of the flowable film to obtain a densified film by providing a third input flow, the third input flow including plasma effluents of a third precursor
Data Source
AI summary
A method includes depositing a flowable film on a substrate by providing a first input flow, the first input flow including plasma effluents of a first precursor, removing a portion of the flowable film from a sidewall of a feature defined within the substrate to obtain a remaining portion of the flowable film by providing a second input flow, the second input flow including plasma effluents of a second precursor, reducing hydrogen content of the remaining portion of the flowable film to obtain a densified film by providing a third input flow, the third input flow including plasma effluents of a third precursor, and treating the densified film in accordance with a film treatment process.