US 11,754,541 B2
Fluorine detection in a gas discharge light source
Joshua Jon Thornes, San Diego, CA (US); Rahul Ahlawat, San Diego, CA (US); Edward Siqi Luo, San Diego, CA (US); and Gamaralalage G. Padmabandu, San Diego, CA (US)
Assigned to Cymer, LLC, San Diego, CA (US)
Appl. No. 16/646,201
Filed by Cymer, LLC, San Diego, CA (US)
PCT Filed Sep. 10, 2018, PCT No. PCT/US2018/050301
§ 371(c)(1), (2) Date Mar. 11, 2020,
PCT Pub. No. WO2019/060164, PCT Pub. Date Mar. 28, 2019.
Claims priority of provisional application 62/562,693, filed on Sep. 25, 2017.
Prior Publication US 2020/0340965 A1, Oct. 29, 2020
Int. Cl. G01N 7/00 (2006.01); G01N 33/00 (2006.01); H01S 3/036 (2006.01); H01S 3/225 (2006.01)
CPC G01N 33/0052 (2013.01) [G01N 33/0013 (2013.01); H01S 3/036 (2013.01); H01S 3/225 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method comprising:
receiving at least a portion of a mixed gas from a gas discharge chamber, wherein the mixed gas includes fluorine;
reacting the fluorine in the mixed gas portion with a metal oxide to form a new gas mixture including oxygen;
sensing a concentration of oxygen within the new gas mixture;
estimating a concentration of fluorine within the mixed gas portion based on the sensed concentration of oxygen; and
determining whether the concentration of fluorine in the new gas mixture falls below a lower value;
wherein sensing the concentration of oxygen within the new gas mixture comprises sensing the concentration of oxygen within the new gas mixture only if it is determined that the concentration of fluorine in the new gas mixture has fallen below the lower value.