Vapor Deposition Using Multiple Source Vessels for Uniform Film
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Solution Overview
Problem
Existing vapor deposition techniques, such as ALD, face challenges in achieving uniform and conformal thin film deposition over high aspect ratio features like deep trenches in semiconductor devices, resulting in inconsistent step coverage and quality issues due to precursor concentration depletion and temperature limitations.
Innovation Solution
The use of multiple source chemical vessels to deliver consistent pulses of the same source chemical simultaneously or alternately, maintaining high partial pressures and controlled temperatures to ensure saturated precursor delivery, thereby enhancing the concentration and uniformity of the deposited film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single source chemical vessel is used to deliver precursor in vapor deposition, then the device complexity is low, but the precursor concentration depletes over time leading to inconsistent film deposition and poor step coverage
Solution Approach 1:
The single source vessel is segmented into multiple source vessels (first source vessel and second source vessel), each capable of independently delivering the source chemical. This segmentation allows continuous supply of fresh precursor without depletion, ensuring consistent film deposition uniformity across the substrate.
Solution Approach 2:
The system discards the depleted source chemical in one vessel and recovers by switching to another vessel containing fresh source chemical. This allows continuous operation without interruption, maintaining consistent precursor concentration throughout the deposition process.
2Productivity
If the substrate temperature is increased to enhance deposition rate, then the productivity improves, but the source chemical condenses on chamber walls leading to contamination and reduced film quality
Solution Approach 1:
The deposition process is segmented into multiple cycles, alternating between two source vessels. This allows the substrate to be exposed to source chemical in controlled pulses rather than continuous exposure, enabling temperature optimization that balances deposition rate with film quality by preventing wall condensation.
Solution Approach 2:
The system employs periodic action by alternating between first and second source vessels in repeated cycles. Each cycle delivers source chemical in controlled pulses, allowing the chamber temperature to be maintained in an optimal range that achieves high deposition rates without causing source chemical to condense on chamber walls.
3Manufacturing precision
If multiple source vessels are used to maintain high precursor concentration, then the film uniformity improves, but the device complexity and operational complexity increase
Solution Approach 1:
The system segments the source supply into two independent vessels, each capable of operating autonomously. This segmentation simplifies control by allowing each vessel to be independently managed, reducing the operational complexity compared to managing a single vessel with complex flow control.
Solution Approach 2:
The system merges the functionality of multiple source vessels with a unified control mechanism that alternates between them. This combination achieves high film uniformity and step coverage while maintaining relatively simple operation through automated alternating cycles between vessels.
4Manufacturing precision
If the deposition cycle time is extended to improve film quality, then the manufacturing precision improves, but the productivity decreases
Solution Approach 1:
The system uses periodic action by alternating between two source vessels in rapid cycles. This allows shorter individual exposure times per vessel while maintaining overall deposition quality, thereby increasing throughput without sacrificing conformality.
Solution Approach 2:
While one source vessel is delivering precursor, the other can be prepared or purged, ensuring continuous useful action without idle time. This continuous operation improves productivity by eliminating cycle interruptions while maintaining film quality through consistent precursor supply.
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 achieves high and repeatable doses of source chemicals, resulting in conformal thin films with step coverage of at least 80% over high aspect ratio features, improving film quality and reducing contamination and leakage current in semiconductor devices.
Implementation Method 1
delivering pulses of a vapor containing a first source chemical to the reaction space from at least two separate source vessels simultaneously
Implementation Method 2
maintaining high partial pressures and controlled temperatures to ensure saturated precursor delivery
Implementation Method 3
a substrate on which deposition is to be conducted is maintained at a temperature above the condensation temperature for the vapor phase reactants
Implementation Method 4
ALD is a chemically self-limiting process in which alternating pulses of source chemicals saturate the substrate and leave no more than a monolayer of material per pulse
Implementation Method 5
The capability of layering atomically thin monolayers enables forming more precise concentration gradients
Data Source
AI summary
Methods of vapor deposition include multiple vapor sources. A vapor deposition method includes delivering pulses of a vapor containing a first source chemical to a reaction space from at least two separate source vessels simultaneously. The pulses can contain a substantially consistent concentration of the first source chemical. The method can include purging the reaction space of an excess of the first source chemical after the delivering, and delivering pulses of a vapor containing a second source chemical to the reaction space from at least two separate source vessels simultaneously after the purging.