Precursor Delivery System Uniform Gas Flow
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Solution Overview
Problem
Current precursor delivery systems for atomic layer deposition fail to provide consistent precursor concentrations over time, leading to irregular deposition and potential device failure, especially as device surface areas increase, and often introduce solid particles into the deposition process.
Innovation Solution
A precursor delivery system comprising a reservoir with an inlet and outlet line, a controller that manages the opening and closing of valves to maintain a high reservoir pressure and ensure a uniform gas flow, preventing solid particles from entering the processing chamber by only allowing one valve to be open at a time, and using a fast pulsing valve to control gas delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the surface area of devices increases to meet growing device requirements, then the precursor amount required for complete saturation increases, but the consistency of precursor concentration delivery becomes more difficult to maintain
Solution Approach 1:
The reservoir is pre-charged with a large amount of precursor gas before the deposition process. This preliminary action ensures that sufficient precursor is available to saturate large surface areas while maintaining consistent concentration throughout the pulse duration, as the precursor is already prepared and pressurized in the reservoir.
Solution Approach 2:
A reservoir acts as an intermediary component between the precursor source and the deposition chamber. This reservoir buffers and stabilizes the precursor supply, ensuring consistent concentration delivery to large surface area devices by decoupling the precursor storage from the delivery process.
2Productivity
If current delivery systems are used, then precursor can be delivered to the substrate, but the precursor concentration varies over time with higher concentration at the beginning of pulses and process
Solution Approach 1:
The reservoir is pre-charged with precursor gas to a high pressure before the deposition process begins. This preliminary pressurization ensures that the precursor concentration remains stable throughout the pulse duration, eliminating the concentration decay observed in conventional systems where precursor is delivered without pre-pressurization.
Solution Approach 2:
The system changes the pressure parameter by pre-pressurizing the reservoir to a high pressure (e.g., 100-1000 psig). This parameter change maintains a stable concentration gradient that drives consistent precursor flow throughout the pulse, preventing the concentration variations that occur in atmospheric pressure delivery systems.
3Ease of operation
If conventional delivery systems operate without strict valve control, then the system is simpler to operate, but solid particles of precursors can enter the processing chamber causing deposition defects
Solution Approach 1:
The outlet valve operates in a periodic sequence: closed during precursor charging to prevent particle escape, then opened for a controlled duration to deliver the precursor pulse, then closed again. This periodic valve operation ensures that solid particles remain contained in the reservoir during charging while allowing clean gas-phase precursor delivery during the pulse.
Solution Approach 2:
The outlet valve acts as an intermediary control element that mediates between the charged reservoir and the deposition chamber. By strictly controlling valve timing and position, it prevents solid particles from entering the chamber while maintaining simple operation through automated controller management.
4Productivity
If the outlet valve is opened to deliver precursor, then gas flow is provided to the chamber, but the flow uniformity decreases without proper pressure control
Solution Approach 1:
The system changes the pressure parameter by pre-pressurizing the reservoir to a high pressure (100-1000 psig) before pulse delivery. This high initial pressure creates a strong driving force that maintains uniform gas flow velocity and precursor concentration throughout the pulse duration, ensuring uniform deposition across the substrate surface.
Solution Approach 2:
The reservoir is pre-charged to a high pressure state before the deposition process. This preliminary pressurization action ensures that when the outlet valve opens, the precursor gas flows uniformly and consistently throughout the pulse duration, preventing flow rate variations that would cause deposition non-uniformity.
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 solution enables consistent, high-concentration precursor pulses with reduced solid particle entrainment, ensuring uniform deposition across the substrate surface, even on high surface area devices, thereby improving the reliability of atomic layer deposition processes.
Implementation Method 1
The controller is configured to close the outlet valve to pressurize the reservoir
Implementation Method 2
open the outlet valve to provide a uniform flow of gas from the reservoir through the outlet line
Data Source
AI summary
A precursor delivery system is described herein. Some embodiments provide a precursor delivery system capable of providing a uniform gas flow comprising precursor into a processing chamber for atomic layer deposition processes. Some embodiments of the precursor delivery system comprise a reservoir with an inlet line, an outlet line and an outlet valve. Further embodiments comprise a precursor source, an inlet valve, a heater, a processing chamber and a controller. Additional embodiments relate to methods for using a precursor delivery system.