Bubbler Precursor Fill Level Measurement via Gas Displacement
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Solution Overview
Problem
Conventional methods for determining the fill level of precursors in bubblers, especially with solid precursors, are difficult and costly, as they often require breaking leaktight seals or using expensive instrumentation, and do not effectively work for solid precursors.
Innovation Solution
The method involves backfilling the bubbler and vapor-delivery system with a known dose of gas, determining pressure and temperature, and using the ideal gas law to calculate the total volume, allowing for the precise determination of the precursor fill level by measuring the difference in total volumes before and after precursor consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional weighing methods are used to determine precursor fill level, then measurement can be performed, but leaktight seals must be broken and gas lines exposed to air contamination
Solution Approach 1:
The patent introduces a mediator substance (gas or liquid) that can be introduced into the bubbler through existing seals to displace the precursor. This mediator acts as an intermediary that enables volume measurement without breaking seals, thus resolving the contradiction between measurement capability and seal integrity maintenance
Solution Approach 2:
The patent replaces the mechanical weighing system (which requires breaking seals) with a gas/liquid displacement system that uses pressure and volume measurements. This substitution eliminates the need to break leaktight seals while still enabling accurate precursor quantity determination
2Measurement precision
If capacitance probing or ultrasonic detection techniques are used, then precursor level can be measured, but the instrumentation cost is very high
Solution Approach 1:
The patent employs simple, low-cost components such as pressure sensors and known gas/liquid volumes to perform measurements that would otherwise require expensive specialized instrumentation. The method uses readily available materials and standard sensors rather than costly dedicated measurement devices
Solution Approach 2:
The patent replaces complex electronic measurement systems (capacitance probes, ultrasonic transducers) with a simpler mechanical/physical displacement method using gas or liquid. This substitution dramatically reduces instrumentation cost while maintaining measurement capability
3Measurement precision
If pressure head measurement is used for liquid precursors, then fill level can be determined, but the technique does not work at all for solid precursors
Solution Approach 1:
The patent creates a universal measurement method that works for both liquid and solid precursors by using gas or liquid displacement. The same basic principle and apparatus can measure precursor volume regardless of whether the precursor is in liquid or solid form, thus achieving versatility across different precursor types
Solution Approach 2:
The patent changes the measurement parameter from pressure head (which only works for liquids) to gas/liquid displacement volume (which works for both liquids and solids). This parameter change enables the measurement technique to be applied universally to different precursor states
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 approach provides a cost-effective and accessible method to accurately monitor precursor levels, enabling efficient precursor management and maintaining a constant fill level in bubblers, reducing the need for frequent replacements and minimizing air contamination.
Implementation Method 1
A total volume for the backfill gas in the bubbler and vapor-delivery system are determined from (1) the determined pressure, (2) the determined temperature and, (3) the known dose by application of a gas law. In some instances, the gas law is the ideal gas law.
Implementation Method 2
Precursor from the bubbler is vaporized and flowed with a carrier gas to the substrate processing chamber
Implementation Method 3
Precursor from the bubbler is vaporized and flowed with a carrier gas to the substrate processing chamber
Data Source
AI summary
Methods are disclosed of determining a fill level of a precursor in a bubbler. The bubbler is fluidicly coupled with a substrate processing chamber through a vapor-delivery system. The bubbler and vapor-delivery system are backfilled with a known dose of a backfill gas. A pressure and temperature of the backfill gas are determined, permitting a total volume for the backfill gas in the bubbler and vapor-delivery system to be determined by application of a gas law. The fill level of the precursor in the bubbler is determined as a difference between (1) a total volume of the bubbler and vapor-delivery system and (2) the determined total volume for the backfill gas.