Substrate processing gas, storage container, and substrate processing method

#The present invention relates to a substrate processing gas, a storage container, and a substrate processing method.

#Various studies on a technique for producing IF7 gas (iodine heptafluoride) have been conducted. As this type of technique, for example, a technique described in Patent Document 1 is known. In Patent Document 1, while supplying a fluorine gas with circulation, iodine pentafluoride which is another raw material is gasified, and both gases are mixed and react in a gas state (claim 1, paragraph 0001, and the like in Patent Document 1). Thus, obtained gases are an unreacted iodine pentafluoride gas, a product iodine heptafluoride gas, and an unreacted fluorine gas, and are separated and recovered as follows, by utilizing the fact that each gas is liquefied at different temperatures. Specifically, it is described that the iodine pentafluoride is cooled and collected by IF5 cold trap 40, iodine heptafluoride is cooled and collected by IF7 cold trap 44, and iodine heptafluoride collected in the IF7 cold trap 44 is gasified by switching the cooling to heating and transferred (recovered) to IF7 recovery cylinder 66 (paragraph 0020 in Patent Document 1).

#[Patent Document 1] Japanese Unexamined Patent Publication No. 2006-265057

#An outline of a substrate processing gas of the present embodiment will be described.

#The substrate processing gas of the present embodiment contains IF5 and IF7. A content of the IF5 in the substrate processing gas can be set to equal to or more than 1 ppm and equal to or less than 2% on a volume basis with respect to the total amount of the IF5 and the IF7.

#According to findings of the present inventor, it was found in a case where IF7 single gas was used as a substrate processing gas, variation in an etching rate occurred. It was considered that decomposition of IF7 causes the variation in the etching rate, and as a result of proceeding with the study, it was found that the variation in the etching rate of the substrate processing gas can be suppressed by adding a trace amount of IF5 to the IF7. Although a detailed mechanism is not clear, it is considered that the decomposition of the IF7 during storage (IF7→IF5+F2) can be suppressed by the trace amount of IF5.