Split Precursor Source for ALD CVD Mode Switching
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Solution Overview
Problem
Current ALD and CVD reactors have limitations, such as slow gas switching in ALD and inefficient precursor control, making it difficult to achieve both high throughput and uniform film deposition, with CVD reactors not easily adaptable for ALD mode operations.
Innovation Solution
A system that allows a single precursor source to feed precursors into a reactor under different conditions by splitting the flow into continuous and periodic paths, enabling operation in ALD, CVD, and combination modes, with precise control of precursor partial pressures using valves and a controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ALD mode is used with fast gas switching, then film uniformity and purity are improved, but productivity decreases due to slow purging
Solution Approach 1:
The system dynamically switches between ALD and CVD operational modes based on process requirements. The gas flow regime is made variable, allowing transition from pulsed flow (ALD) to continuous flow (CVD), enabling optimization between film quality and deposition rate for different application needs
Solution Approach 2:
The patent changes key process parameters including gas flow rate, precursor partial pressure, and residence time to enable operation in different modes. By adjusting these parameters, the system can achieve high uniformity when needed while maintaining high productivity when required
2Productivity
If CVD mode is used with continuous precursor flow, then productivity increases, but film uniformity and step coverage deteriorate
Solution Approach 1:
The system dynamically adjusts the gas flow regime from continuous (CVD) to pulsed (ALD) based on the desired outcome. This dynamic control allows the system to achieve high deposition rates when productivity is prioritized while maintaining film uniformity when quality is the primary concern
Solution Approach 2:
By changing precursor flow rate and residence time parameters, the system can operate in CVD mode for high productivity applications while switching to ALD mode parameters when film uniformity and step coverage are critical requirements
3Manufacturing precision
If CVD reactor geometry is optimized for uniform concentration distribution, then film uniformity is improved, but adaptability for ALD mode decreases
Solution Approach 1:
The reactor system is designed with multi-functionality, capable of operating in both CVD and ALD modes using the same hardware infrastructure. The gas delivery system and reactor geometry are configured to accommodate both continuous flow (CVD) and pulsed flow (ALD) operational requirements, eliminating the need for dedicated reactors for each mode
Solution Approach 2:
The system makes the gas flow regime dynamic rather than fixed, allowing the same reactor to adapt between continuous flow and pulsed flow modes. This dynamic capability enables a single reactor to achieve both uniform concentration distribution (CVD) and effective precursor pulsing (ALD) by adjusting operational parameters
4Measurement precision
If ALD reactor is designed with small gas volume for fast switching, then precursor control precision is improved, but productivity decreases due to purging time
Solution Approach 1:
By operating in CVD mode or combination mode, the system eliminates the purging step entirely, maintaining continuous precursor flow and continuous film growth. This continuity of useful action removes the time loss associated with purging while still achieving precise precursor control through regulated flow rates and partial pressures
Solution Approach 2:
The system changes the operational parameters from pulsed flow with purging (ALD) to continuous flow without purging (CVD). By adjusting precursor flow rate and residence time parameters, the system achieves precise precursor control in CVD mode while eliminating purging time losses
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
Enables flexible operation of a reactor in multiple modes, improving film step coverage and throughput, achieving high uniformity and low impurity levels, and allowing for better control over the thin film deposition process.
Implementation Method 1
Chemical Vapor deposition (CVD) is based on the continuous flow of a precursor/precursors to the reactor
Implementation Method 2
During normal operation of Atomic Layer Deposition (ALD) reactors, two or more reactants are alternatingly introduced to the reactor
Data Source
AI summary
The present invention relates generally to methods and apparatus for the controlled growing of material on substrates. According to embodiments of the present invention, a precursor fed is split in to two paths from a precursor source. One of the paths is restricted in a continuous manner. The other path is restricted in a periodic manner. The output of the two paths converges at a point prior to entry of the reactor. Therefore, a single precursor source is able to fed precursor in to a reactor under two different conditions, one which can be seen as mimicking ALD conditions and one which can be seen as mimicking CVD conditions. This allows for an otherwise single mode reactor to be operated in a plurality of modes including one or more ALD/CVD combination modes.