Solid Precursor Sublimator with Alternating Shelves
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Solution Overview
Problem
Current solid precursor sublimators face challenges with short contact time between carrier gas and precursors, non-uniform temperature distribution, and maintenance issues, leading to unstable vapor concentrations and reduced operational efficiency.
Innovation Solution
A sublimator apparatus featuring a cylindrical chamber with alternating annular disks that allow for efficient gas flow over the precursors, maximizing contact time and vaporization rates while maintaining stable temperature profiles and minimizing maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solid precursors are freely piled inside a container compartment and heated, then the sublimation process is simple and cost effective, but the carrier gas is not saturated and the precursor vapor concentration is not stable
Solution Approach 1:
The container is segmented into multiple levels with shelves that create distinct zones for precursor placement and gas flow management. This segmentation allows the carrier gas to flow through and over the precursors in a controlled manner, ensuring saturation and stable vapor concentration while maintaining a relatively simple overall structure.
2Stability of the object's composition
If an agitation structure is installed inside the compartment to agitate the solid continuously, then the contact time between carrier gas and solid is increased and channeling flow is eliminated, but the movable part decreases operational efficiency and increases maintenance downtime
Solution Approach 1:
Instead of using a movable agitation structure that stirs the precursors, the invention inverts the approach by using a stationary shelf structure that passively directs gas flow through and over the precursors. The gas flow itself creates the necessary contact and distribution without requiring mechanical agitation, thus eliminating maintenance issues while maintaining gas saturation.
3Area of stationary object
If the solid precursor is coated on cylinder surfaces set concentrically inside a heated container, then the sublimation surface area is increased, but the temperature profile along the surfaces is non-uniform resulting in non-stable sublimation
Solution Approach 1:
The shelf structure provides locally optimized precursor placement zones with controlled gas flow patterns. Each shelf level creates a localized environment where temperature and gas flow are optimized for stable sublimation, ensuring uniform vapor generation across the entire sublimation surface area.
4Stability of the object's composition
If the coated surface is installed on a rotating shaft with spot heating, then smooth sublimation is achieved, but the vaporization rate is limited to low carrier gas flow rates not feasible for industrial scale
Solution Approach 1:
The invention transitions from a single rotating shaft geometry to a multi-level shelf structure that utilizes vertical and horizontal dimensions. This dimensional expansion allows carrier gas to flow through multiple levels simultaneously, dramatically increasing the effective vaporization rate while maintaining uniform sublimation across all shelf levels through controlled gas distribution.
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 apparatus achieves stable, saturated carrier gas with high flow rates and reduced maintenance, enhancing the sublimation efficiency and operational stability for semiconductor manufacturing processes.
Implementation Method 1
These materials generally have very high melting point and low vapor pressure, and must be sublimed within narrow temperature and pressure ranges prior to introduction to a deposition chamber
Implementation Method 2
The compartment is heated to an elevated temperature, and inert carrier gas is introduced into the compartment to carry the sublimed vapor phase downstream for film deposition
Data Source
AI summary
An apparatus and method for holding a solid precursor in a sublimator such that the solid precursor can be vaporized for saturating a carrier gas. The apparatus may include alternating disks or shelves that form inner and outer passages, as well as spaces between the disks for fluidicly coupling the passages to create a winding, tortuous fluid flow path through the sublimator for optimizing solid vapor saturation. The method may include directing a carrier gas into a sublimation chamber, around the first shelf in the outer passage, over the first shelf in the space, around the second shelf in the inner passage, and back out of the sublimation chamber.