Floating Structure Ampoule for Constant Headspace
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Solution Overview
Problem
In semiconductor wafer processing, the varying headspace in ampoules containing liquid precursors leads to non-uniform precursor concentration during deposition, causing inconsistencies in film deposition.
Innovation Solution
The use of ampoules with a floating structure that maintains a constant headspace, comprising a float, an outlet channel, and a baffle, ensures consistent precursor saturation regardless of the liquid chemistry height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the liquid precursor level in the ampoule changes during deposition, then the headspace volume varies, but this causes non-uniform precursor concentration in the carrier gas
Solution Approach 1:
The floating structure dynamically adjusts its position as liquid is consumed or added to the ampoule. The float rises and falls with liquid level changes, maintaining a constant distance between the liquid surface and the outlet channel, thereby keeping the headspace volume constant despite variations in liquid quantity.
Solution Approach 2:
The floating structure acts as an intermediary between the liquid precursor and the carrier gas outlet. By positioning the outlet channel at a fixed distance above the liquid surface through buoyancy-based floating, it mediates the interaction between variable liquid levels and the requirement for constant headspace volume.
2Manufacturing precision
If a simple ampoule design is used, then the device complexity is low, but the precursor delivery uniformity deteriorates
Solution Approach 1:
The ampoule is segmented into distinct functional zones: the liquid precursor reservoir, the floating structure with outlet channel, the saturation zone, and the carrier gas flow path. This segmentation allows each component to perform its specific function optimally while maintaining overall system simplicity.
Solution Approach 2:
The floating structure is self-regulating through buoyancy forces. As liquid level changes, the float automatically adjusts its position without external control mechanisms, maintaining constant headspace volume and ensuring uniform precursor delivery throughout the deposition process.
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
This solution provides consistent precursor concentration and uniform deposition, reducing the impact of changing liquid heights and enabling repeatable deposition rates across wafers and tools.
Implementation Method 1
The float has a top surface and a volume configured to displace a predetermined volume of liquid so that the top surface of the float remains a depth below a surface of the liquid
Implementation Method 2
The baffle is positioned along a length of the outlet channel to create a saturation zone between the bottom surface of the baffle and the surface of the liquid
Implementation Method 3
The precursor molecules in the headspace are swept up in the stream of carrier gas and flow to the processing chamber
Data Source
AI summary
Ampoules including a housing, a lid and a floating structure are described. The floating structure includes a float with a volume determined to displace a predetermined volume of liquid within the ampoule. An outlet channel extends from the top surface of the float. A baffle is positioned along the length of the outlet channel and creates a saturation zone between the baffle and the float.