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Method and system for gas flow mitigation of molecular contamination of optics

United States Patent

January 23, 2018
View the Complete Patent at the US Patent & Trademark Office
Sandia National Laboratories - Visit the Intellectual Property Management and Licensing Website
A computer-implemented method for determining an optimized purge gas flow in a semi-conductor inspection metrology or lithography apparatus, comprising receiving a permissible contaminant mole fraction, a contaminant outgassing flow rate associated with a contaminant, a contaminant mass diffusivity, an outgassing surface length, a pressure, a temperature, a channel height, and a molecular weight of a purge gas, calculating a flow factor based on the permissible contaminant mole fraction, the contaminant outgassing flow rate, the channel height, and the outgassing surface length, comparing the flow factor to a predefined maximum flow factor value, calculating a minimum purge gas velocity and a purge gas mass flow rate from the flow factor, the contaminant mass diffusivity, the pressure, the temperature, and the molecular weight of the purge gas, and introducing the purge gas into the semi-conductor inspection metrology or lithography apparatus with the minimum purge gas velocity and the purge gas flow rate.
Delgado; Gildardo (Livermore, CA), Johnson; Terry (Livermore, CA), Arienti; Marco (Livermore, CA), Harb; Salam (Los Gatos, CA), Klebanoff; Lennie (Dublin, CA), Garcia; Rudy (Union City, CA), Tahmassebpur; Mohammed (San Ramon, CA), Scott; Sarah (Oakland, CA)
KLA-Tencor Corporation (Milpitas, CA), National Technology & Engineering Solutions of Sandia, LLC (Albuquerque, NM)
14/ 466,516
August 22, 2014
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was developed with Government support under Contract No. DE-AC04-94AL85000 between Sandia Corporation and the U.S. Department of Energy. The U.S. Government has certain rights in this invention.