US 12,338,381 B2
Protective fluid for alumina, protection method, and production method for semiconductor substrate having alumina layer using same
Toshiyuki Oie, Katsushika-ku (JP); Priangga Perdana Putra, Katsushika-ku (JP); and Akinobu Horita, Katsushika-ku (JP)
Assigned to MITSUBISHI GAS CHEMICAL COMPANY, INC., Chiyoda-ku (JP)
Appl. No. 16/976,565
Filed by MITSUBISHI GAS CHEMICAL COMPANY, INC., Chiyoda-ku (JP)
PCT Filed Feb. 27, 2019, PCT No. PCT/JP2019/007409
§ 371(c)(1), (2) Date Aug. 28, 2020,
PCT Pub. No. WO2019/167971, PCT Pub. Date Sep. 6, 2019.
Claims priority of application No. 2018-037144 (JP), filed on Mar. 2, 2018.
Prior Publication US 2021/0002551 A1, Jan. 7, 2021
Int. Cl. C09K 15/02 (2006.01); B05D 5/00 (2006.01); C01F 7/021 (2022.01); H01L 21/02 (2006.01)
CPC C09K 15/02 (2013.01) [B05D 5/00 (2013.01); C01F 7/021 (2013.01); H01L 21/0206 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for protecting alumina, the method comprising:
treating at least a portion of a surface of an alumina layer comprising alumina with a protective fluid consisting of (i) water and (ii) barium nitrate, barium acetate, and/or barium chloride in a range of from more than 1 to 20 wt. % together, based on total protective fluid weight, to thereby form a fluid film on the portion of the surface of the alumina layer; and
washing over the fluid film and the alumina layer with an optionally corrosive washing solution,
wherein the treating is at a temperature in a range of from 30 to 60° C. for a time in a range of from 0.2 to less than 60 minutes.