Filterable surfactant composition
View Patent ↗An improved aqueous soluble surfactant which has particular utility for incorporating in etchants for semiconductor devices is provided. The surfactant comprises a combination of a linear perfluorocarboxylic acid, a cyclic amine and an aliphatic alcohol.
1. An aqueous soluble surfactant comprising:
(i) cyclic alkylamine of formula
C x H 2x+1 N or (CH 2 ) x−1 CH NH 2
wherein x is an integer of 5 to 8;
(ii) a linear perfluorocarboxylic acid of the formula
C n F 2n−1 O 2 H or C n−1 F 2n−1 COOH
wherein n is an integer of 4 to 11 and yields a perfluoroamide of the formula
C n−1 F 2n−1 CO NHCH(CH 2 ) x−1
wherein n=4 to 11 and x=5 to 8 when reacted with the cyclic alkylamine and
(iii) an aliphatic alcohol of the formula
C n H 2n+2 O, or C n H 2n+1 OH,
wherein n is an integer of 1 to 5.
2. The soluble surfactant of claims 1 wherein “(ii)” is an aqueous solution comprise of a blend of a cyclic alkylamine, perfluorocarboxylic acid and aliphatic alcohol and wherein the composition comprises at least 1% by weight of the cyclic alkylamine of the formula (CH 2 ) x−1 CHNH 2 , at least 1% by weight of the Perfluorocarboxylic acid of the formula C n−1 F 2n−1 COOH, and at least 10% by weight of the aliphatic alcohol of the formula C n H 2n+1 OH.
3. The aqueous soluble surfactant of claim 1 , wherein “ii” comprises about 10 ppm to about 500 ppm, of a combined quantity of cyclic alkylamine of the formula (CH 2 ) x−1 CHNH 2 and the perfluorocarboxylic acid of the formula C n−1 F 2n−1 COOH, based on the weight of the etchant.
4. The aqueous soluble surfactant of claim 1 wherein the cyclic alkylamine (i) is a member selected from the group consisting of cyclopentylamine, cycloheptylamine, and cyclooctylamine.
5. The aqueous soluble surfactant of claim 1 wherein the linear perfluorocarboxylic acid (ii) of the formula C n−1 F 2n−1 COOH is a member selected from the group consisting of tridecafluoroheptanoic acid (perfluoroheptanoic acid), pentadecafluorooctanoic acid (perfluorooctanoic acid), heptafluorobutyric acid (perfluorobutanoic acid), and heptadecafluorononanoic acid (perfluorononanoic acid).
6. The aqueous soluble surfactant of claim 1 wherein the alcohol (iii) of the formula C n H 2n+1 OH is a member selected from the group consisting of 2-propanol, 1-propanol, ethanol, methanol, and 1-butanol.