Bottom-Fed Ampoule Design for Semiconductor Precursor Saturation
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Solution Overview
Problem
Existing ampoule designs for semiconductor manufacturing precursors with low vapor pressure suffer from inadequate residence time for carrier gas saturation, uneven gas distribution, and precursor dust migration issues, leading to inconsistent precursor delivery and particle contamination.
Innovation Solution
A bottom-fed ampoule design with a tortuous flow path and filter media to increase dwell time and prevent precursor dust migration, ensuring consistent carrier gas saturation and even distribution across the precursor surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a conventional top-fed sublimation ampoule design is used, then the structure is simple, but the carrier gas residence time is insufficient and saturation is inconsistent
Solution Approach 1:
The ampoule is segmented into multiple functional zones: a sublimation zone with concentric elongate walls for precursor placement, a filter media layer for particle removal, and a carrier gas flow path. This segmentation allows the carrier gas to traverse through multiple stages (sublimation → filtration → outlet), extending residence time while maintaining manageable structural complexity through modular zonation
Solution Approach 2:
Concentric elongate walls are nested within the ampoule, creating multiple flow channels between them. The carrier gas flows through the spaces between these nested walls, effectively increasing the flow path length and residence time without proportionally increasing the external dimensions or complexity of the ampoule structure
2Quantity of substance
If the head space of the ampoule is increased, then more carrier gas can be accommodated, but concentration consistency deteriorates
Solution Approach 1:
The ampoule design creates different local zones with specific functions: the sublimation zone concentrates precursor material on the concentric walls, the filter media zone removes particles, and the flow channels ensure uniform gas distribution. This local differentiation maintains consistent saturation despite varying total gas volumes, as each zone performs its specific function optimally
Solution Approach 2:
Filter media with controlled porosity is introduced between the sublimation zone and outlet. This porous layer allows carrier gas to pass through while trapping precursor particles, ensuring that increased gas volume does not compromise concentration consistency. The filter media provides a transition zone that maintains saturation uniformity across varying head space volumes
3Reliability
If solid precursor is used with low vapor pressure, then the precursor can be stored stably, but carrier gas saturation becomes inadequate
Solution Approach 1:
The solid precursor is pre-positioned on the concentric elongate walls in the sublimation zone, creating a large surface area contact region before carrier gas introduction. This preliminary arrangement ensures that when carrier gas flows through the ampoule, it immediately encounters saturated vapor from the pre-positioned precursor, compensating for the low vapor pressure through extended contact time and increased surface area
Solution Approach 2:
The design exploits the sublimation phase transition of solid precursor (solid → vapor) to generate carrier gas saturation. By providing a large surface area of solid precursor on the concentric walls and maintaining appropriate temperature, continuous sublimation occurs, ensuring adequate saturation of the carrier gas even for low vapor pressure materials throughout the extended residence time
4Ease of manufacture
If conventional ampoule design is used, then manufacturing is simple, but precursor dust migrates to control valves
Solution Approach 1:
Filter media is introduced as an intermediary component between the sublimation zone and the outlet conduit. This filter media layer captures precursor particles that might otherwise migrate with the carrier gas to control valves and downstream equipment. The filter media serves as a protective barrier that removes harmful particles while allowing carrier gas to pass through, adding minimal manufacturing complexity
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 design achieves consistent precursor delivery by extending the carrier gas residence time within the ampoule, maintaining saturation levels as the solid precursor depletes, and preventing dust from reaching control valves, thus enhancing the uniformity and reliability of semiconductor manufacturing processes.
Implementation Method 1
sublimation occurs between the top surface of the solid precursor and the carrier gas within the head space
Data Source
AI summary
Bottom-fed ampoules for a semiconductor manufacturing precursors and methods of use are described. The ampoules comprise an outer cylindrical wall and an inner cylindrical wall defining a flow channel in between and a bottom wall having a top surface with a plurality of concentric elongate walls, each wall comprising an opening offset from the opening in adjacent walls defining a gas exchange zone through which a carrier gas flows in contact with the precursor.