Porous Vaporizer for Solid Source Reagent Particle Suppression
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Solution Overview
Problem
Existing vaporizer systems for chemical vapor deposition (CVD) and ion implantation face challenges in achieving thermal homogeneity and controlling the vaporization of source reagents, leading to uneven vapor generation and the production of unwanted by-products, particularly with solid source reagents that are susceptible to thermal decomposition.
Innovation Solution
The development of a vaporizer apparatus with structural conformations that include particle suppression features, such as thermally conductive foam materials and porous metal bodies, to support and heat source reagents, ensuring uniform vaporization and minimizing particle entrainment, along with the use of ionic liquids and specific particle size distributions for solid source reagents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solid source reagents are heated to generate vapor, then vapor generation is achieved, but thermal decomposition occurs and produces unwanted by-products
Solution Approach 1:
The patent employs porous graphite bodies as heating elements and porous support structures to hold the solid source reagent. The porous structure increases the surface area for heat transfer, enabling more uniform and efficient vapor generation at lower temperatures, thereby reducing thermal decomposition. The porous material allows carrier gas to flow through and contact the source reagent effectively.
Solution Approach 2:
The patent controls the temperature parameters carefully, heating the vaporizer vessel to a temperature sufficient for sublimation or vaporization but below the decomposition temperature of the source reagent. The system adjusts heating parameters to maintain thermal homogeneity throughout the source reagent, preventing localized hot spots that would cause decomposition.
2Stability of the object's composition
If solid source reagents are heated uniformly, then thermal homogeneity is achieved, but particle entrainment in vapor increases
Solution Approach 1:
The patent uses localized heating zones and specific geometric configurations of the heating elements to create optimal temperature distributions. The protrusion elements and porous structures are positioned to ensure uniform heat distribution across the source reagent while minimizing areas where particles could be entrained. The system creates different local conditions: uniform heating zones for vapor generation and cooler zones for particle settlement.
Solution Approach 2:
The patent introduces a carrier gas as an intermediary medium that flows through the vaporizer vessel, picking up the vaporized source reagent while leaving behind any particles. The carrier gas stream helps separate vapor from particles through differential transport, with the vapor being carried forward and particles settling or being filtered out.
3Productivity
If heating temperature is increased to improve vapor generation rate, then productivity increases, but thermal decomposition and by-product formation worsen
Solution Approach 1:
The porous heating elements and support structures provide large surface area for heat transfer, enabling efficient vapor generation at moderate temperatures. This allows the system to achieve high vapor generation rates without excessive temperature increases, maintaining process reliability by staying below decomposition thresholds.
Solution Approach 2:
The patent transitions from conventional heating methods to a three-dimensional porous structure that distributes heat throughout the volume of the source reagent. This dimensional approach allows uniform heating from multiple directions simultaneously, achieving high vapor generation rates while maintaining temperatures below decomposition points.
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 solution enables reproducible and controlled vapor generation with reduced particle presence, improving the efficiency and reliability of vaporization processes in CVD and ion implantation, while minimizing thermal degradation and by-product formation.
Implementation Method 1
thermally conductive foam materials and porous metal bodies, to support and heat source reagents
Implementation Method 2
solid source reagents that are susceptible to thermal decomposition
Implementation Method 3
heating to form the source reagent vapor for deposition or implantation
Data Source
AI summary
Apparatus and method for volatilizing a source reagent susceptible to particle generation or presence of particles in the corresponding source reagent vapor, in which such particle generation or presence is suppressed by structural or processing features of the vapor generation system. Such apparatus and method are applicable to liquid and solid source reagents, particularly solid source reagents such as metal halides, e.g., hafnium chloride. The source reagent in one specific implementation is constituted by a porous monolithic bulk form of the source reagent material. The apparatus and method of the invention are usefully employed to provide source reagent vapor for applications such as atomic layer deposition (ALD) and ion implantation.