Bottom-fed Sublimation Ampoule with Tortuous Flow Path
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Solution Overview
Problem
Existing ampoule designs for semiconductor manufacturing precursors with low vapor pressure fail to provide adequate residence time for carrier gas saturation and even distribution, leading to inconsistent precursor delivery and particle issues.
Innovation Solution
A bottom-fed ampoule with a tortuous flow path and filter media assembly that increases dwell time for carrier gas, ensuring consistent saturation and preventing precursor dust migration, utilizing a serpentine manifold and gas ring for efficient sublimation and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a conventional top-fed ampoule design is used with a short flow path, then the device complexity is low, but the residence time for carrier gas saturation is insufficient leading to inconsistent precursor delivery
Solution Approach 1:
The ampoule is divided into distinct functional zones: a sublimation zone at the bottom containing the solid precursor, a mixing zone in the middle where carrier gas mixes with sublimed vapor, and a delivery zone at the top. This segmentation allows each zone to perform its specific function optimally, extending the effective residence time without significantly increasing overall device complexity
Solution Approach 2:
The invention transitions from a conventional top-fed single-direction flow to a bottom-fed upward flow configuration, utilizing the vertical dimension more effectively. The carrier gas flows upward through the sublimation zone, creating a longer interaction path between the gas and sublimed precursor vapor, thereby increasing residence time without proportionally increasing device volume or complexity
2Area of stationary object
If the head space of the ampoule is increased to allow more sublimation area, then the surface area for sublimation is improved, but the concentration of saturated carrier gas becomes inconsistent
Solution Approach 1:
The ampoule design creates different local conditions in different zones: the bottom sublimation zone maintains high precursor vapor concentration, the middle mixing zone allows for thorough mixing and saturation, and the top delivery zone maintains consistent saturated concentration. Each zone is optimized for its specific function, ensuring uniform saturation despite the large overall surface area
Solution Approach 2:
The bottom-fed configuration ensures continuous upward flow of carrier gas through the sublimation zone, maintaining continuous contact between the gas and sublimed precursor vapor. This continuous action ensures consistent saturation concentration throughout the flow path, preventing the inconsistency that would occur with larger head spaces in conventional designs
3Ease of operation
If conventional ampoule designs are used without even distribution, then the device complexity is low, but the carrier gas does not evenly distribute across the precursor surface
Solution Approach 1:
The gas distribution system is segmented into multiple gas inlet ports positioned at the bottom of the ampoule, with gas flowing upward through multiple vertical channels. This segmentation of the flow path ensures that carrier gas is distributed evenly across the entire precursor surface area, achieving uniform saturation without requiring complex distribution mechanisms
4Object-affected harmful factors
If existing ampoule designs are used without dust prevention, then the device complexity is low, but precursor dust travels downstream causing control valve performance issues and on-wafer particle issues
Solution Approach 1:
A filter element is introduced into the gas flow path at the top of the ampoule, just before the gas exits to the delivery system. This filter extracts and removes any precursor dust or particulates from the carrier gas stream, preventing downstream contamination of control valves and on-wafer particles, while adding minimal complexity to the overall device
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 achieves consistent precursor delivery and prevents particle issues by ensuring adequate residence time for carrier gas saturation and even distribution, maintaining concentration uniformity and preventing precursor dust migration.
Implementation Method 1
The manifold comprises a hollow cylindrical shaft with an outlet and a serpentine base positioned at a bottom end of the shaft, the serpentine base has a top surface and a bottom surface, the bottom surface has a plurality of elongate walls extend therefrom, each of the elongate walls having a plurality of openings in adjacent elongate walls off-set from one another forming a torturous flow path.
Implementation Method 2
The filter media assembly comprises a first filter media and a frame, the first filter media having a porosity such that vaporized precursor can pass through.
Implementation Method 3
The filter media assembly is in contact with the bottom end of the shaft forming a sublimation cavity between a bottom surface of the filter media assembly and the top surface of the bottom wall, the sublimation cavity including the bottom end of the shaft and the serpentine base.
Implementation Method 4
The gas ring positioned below the filter media assembly such that carrier gas is distributed across a bottom surface of the filter media assembly.
Data Source
AI summary
Ampoules for a semiconductor manufacturing precursors and methods of use are described. The ampoules include a container with an inlet port an outlet port, a manifold having a serpentine base creating a tortuous flow path and a filter media assembly in a bottom-fed configuration. The torturous flow path is defined by a plurality of elongate walls and a plurality of openings of the serpentine base ampoule, through which a carrier gas flows in contact with the precursor.