Multi-tray vapor draw system for high-viscosity precursors
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Solution Overview
Problem
Existing systems face challenges in vaporizing liquid precursors with low vapor pressure and high viscosity, as they tend to re-condense and are not efficiently atomized, limiting the flow rate of vaporized precursors to substrate processing tools like CVD and ALD systems.
Innovation Solution
A multi-tray system with increased surface area interaction between carrier gas and liquid precursor, using multiple trays and strategically arranged openings for carrier gas flow, along with heat transfer enhancement and vibration to improve evaporation rates, allowing for higher vapor flow rates and efficient precursor delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct liquid injection is used to vaporize precursors, then the system is simple, but high viscosity liquids do not atomize easily and cannot be vaporized effectively
Solution Approach 1:
The system divides the liquid precursor into multiple thin films across multiple trays, increasing the total surface area available for vaporization. This segmentation allows the carrier gas to interact with larger portions of the liquid surface simultaneously, overcoming the atomization difficulty of high viscosity liquids without requiring direct injection.
Solution Approach 2:
The invention transitions from a single-point injection approach to a multi-dimensional surface interaction system. By arranging multiple trays vertically and allowing carrier gas to flow across liquid surfaces at different heights, the system exploits the vertical dimension to increase the effective vaporization area and efficiency.
2Productivity
If carrier gas flow rate is increased to transport more vaporized precursor, then productivity improves, but splashing concerns limit the maximum flow rate in standard bubblers
Solution Approach 1:
The system segments the liquid- gas interaction into multiple discrete trays, where carrier gas flows across the surface of each tray sequentially. This segmentation prevents the gas from penetrating deeply into a single large liquid volume, reducing splashing while maintaining high vaporization efficiency through increased surface area exposure.
Solution Approach 2:
The system uses multiple trays to provide excess surface area for vaporization, allowing the carrier gas to achieve saturation without requiring excessive flow rates that would cause splashing. The partial exposure of gas to multiple liquid surfaces enables efficient precursor uptake at moderate flow rates.
3Productivity
If single surface flow-over systems increase total pressure to enable vapor flow, then precursor can be transported, but the carrier gas does not saturate with vapor and the amount of vaporized precursor transported is relatively low
Solution Approach 1:
The system segments the vaporization process across multiple trays, allowing carrier gas to become saturated with precursor vapor at each tray surface. This multi-stage saturation process ensures that the gas leaves each tray with maximum precursor loading, significantly increasing the total quantity of vaporized precursor transported compared to single-surface systems.
Solution Approach 2:
The system maintains continuous interaction between carrier gas and liquid precursor across multiple trays in series. The carrier gas continuously picks up precursor vapor at each tray surface, ensuring that the useful action of vapor saturation occurs repeatedly and continuously throughout the multi-tray assembly, maximizing the quantity of precursor transported.
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 system effectively increases precursor evaporation rates, enabling higher flow rates of vaporized precursors to substrate processing chambers, even for medium vapor pressure precursors, by optimizing the interaction between carrier gas and liquid precursor, thus improving processing efficiency.
Implementation Method 1
The plurality of openings is configured to direct the carrier gas across the liquid precursor in the plurality of trays, respectively. The output of the enclosure provides a mixture of the carrier gas and the vaporized precursor.
Implementation Method 2
systems and methods for vaporizing precursors with low to medium vapor pressure typically include vapor draw, bubblers or flow over a single surface of liquid inside an ampoule
Implementation Method 3
along with heat transfer enhancement and vibration to improve evaporation rates
Implementation Method 4
along with heat transfer enhancement and vibration to improve evaporation rates
Data Source
AI summary
A system for supplying vaporized precursor includes an enclosure including an output. A plurality of trays is arranged in a stacked, spaced configuration inside the enclosure. The plurality of trays is configured to hold liquid precursor. A first conduit fluidly connects a carrier gas supply to the enclosure and includes a plurality of openings. A first valve is arranged along the first conduit and is configured to selectively control delivery of the carrier gas from the carrier gas supply through the first conduit to the plurality of openings in the first conduit. The plurality of openings is configured to direct the carrier gas across the liquid precursor in the plurality of trays, respectively. The output of the enclosure provides a mixture of the carrier gas and the vaporized precursor.