	US 12,134,724 B2
	Etching composition
Jeong Sik Oh, Gyeonggi-do (KR); Tae Ho Kim, Gyeonggi-do (KR); Gi Young Kim, Gyeonggi-do (KR); Myung Ho Lee, Gyeonggi-do (KR); and Myung Geun Song, Gyeonggi-do (KR)
Filed by ENF TECHNOLOGY CO., LTD., Gyeonggi-do (KR)
Filed on May 9, 2022, as Appl. No. 17/739,489.
Claims priority of application No. 10-2021-0068868 (KR), filed on May 28, 2021.
Prior Publication US 2022/0403243 A1, Dec. 22, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C09K 13/08 (2006.01)

CPC C09K 13/08 (2013.01)

13 Claims

1. An etching composition comprising:

a fluorine compound;

sulfuric acid;

nitrosylsulfuric acid; and

an inorganic acid or a salt thereof,

wherein the inorganic acid or a salt thereof is not a fluorine compound, sulfuric acid, nitrosylsulfuric acid, or a silicon compound, wherein the composition comprises at least 87% by weight of total fluorine compound, sulfuric acid, and nitrosylsulfuric acid, wherein the composition comprises from about 50 to about 95% by weight of sulfuric acid, and wherein the composition selectively etches silicon relative to silicon oxide.

12. A method for preparing an etching composition, comprising mixing:

0.3 to 30% by weight of a fluorine compound,

50 to 95% by weight of sulfuric acid,

1 to 30% by weight of nitrosylsulfuric acid,

0.01 to 15% by weight of an inorganic acid and a salt thereof; and

the balance of water to make 100% by weight of the total weight of composition,

wherein the inorganic acid or a salt thereof is not a fluorine compound, sulfuric acid, a silicon compound and a salt thereof, and wherein the composition comprises at least 87% by weight of total fluorine compound, sulfuric acid, and nitrosylsulfuric acid.