SLowFlowS: A novel flow standard for semiconductor process gases.

Area of Science:

• Metrology
• Semiconductor Manufacturing
• Fluid Dynamics

Background:

• Accurate metering of semiconductor process gases is crucial for chip production efficiency and yield.
• The absence of a national flow standard necessitates approximations (meter factors) for gas calibration.
• Current methods using nitrogen calibration for process gases introduce inaccuracies.

Purpose of the Study:

• To develop a novel national flow standard for semiconductor process gases.
• To enable accurate modeling of gas species effects on commercial flow meters and controllers.
• To allow meters calibrated with nitrogen to accurately measure hazardous process gases.

Main Methods:

• Development of a rate-of-rise flow standard (SLowFlowS) with a unique collection tank geometry (long, slender tubing).
• Implementation of an air bath for enhanced thermal stability and accurate temperature prediction.
• Experimental validation of the thermodynamic model, flow standard testing, and uncertainty analysis.

Main Results:

• The SLowFlowS standard achieves an expanded uncertainty (95% confidence) between 0.056% and 0.098%.
• The standard covers a wide flow range from 0.01 cm³/min to 1000 cm³/min.
• Accurate temperature prediction and heat transfer were confirmed during the filling process.

Conclusions:

• The developed SLowFlowS provides a reliable national flow standard for semiconductor process gases.
• This standard will significantly improve the accuracy of gas flow measurements in semiconductor fabrication.
• It enables precise calibration and modeling, leading to enhanced semiconductor device yield and throughput.