Method for suppressing collapse of three-dimensional structure
A method for suppressing collapse of a three-dimensional structure which can hydrophobize a surface of a three-dimensional structure on a substrate, regardless of a material of the substrate and a material of the three-dimensional structure, and can suppress collapse of the three-dimensional structure on the substrate, as a result of hydrophobization, a surface treatment liquid, a method for producing the surface treatment liquid, and a substrate having a three-dimensional structure with silane condensate that is a component of the surface treatment liquid and is attached or bound to a surface of the three-dimensional structure. The method includes preparing a substrate having a three-dimensional structure on a surface thereof, and contacting a surface treatment liquid to a surface of the three-dimensional structure, a surface treatment liquid including a silane condensate that is a silane condensate formed by hydrolyzation condensation of a hydrolyzable silane compound including a trifunctional silane compound having a specific structure.
1 . A method for suppressing collapse of a three-dimensional structure comprising:
preparing a substrate having a patterned three-dimensional structure on the surface thereof, and
contacting a surface treatment liquid to the surface of the three-dimensional structure, wherein, the surface treatment liquid comprises a silane condensate (A), and an organic solvent (S),
the silane condensate (A) is a condensate formed by hydrolyzation condensation of a hydrolyzable silane compound comprising a trifunctional silane compound (A1) represented by the following formula (A1-1):
SiR a1 (R a2 ) 3 (A1-1)
wherein, in the formula (A1-1), R a1 is a hydrocarbon group having 1 or more and 20 or less carbon atoms, R a2 is a group capable of forming a silanol group by hydrolysis, and three R a2 s may be the same as or different from each other,
a concentration of the silane condensate (A) in the surface treatment liquid is 0.00005% by mass or more and 40% by mass or less,
a total content of a trimer, a tetramer, and a pentamer in each oligomer in the silane condensate (A) is 50% by area or more and 100% by area or less with respect to a total area of the silane condensate (A),
a content of the tetramer in the silane condensate (A) is 30% by area or more and 70% by area or less with respect to the total area of the silane condensate (A), and
the % by area is an area percentage for each oligomer in an obtained chromatogram, when the silane condensate (A) is analyzed by gel permeation chromatography (GPC).
2 . The method for suppressing collapse of the three-dimensional structure according to claim 1 , wherein the hydrolyzation condensation of the hydrolyzable silane compound is carried out in a reaction liquid comprising the organic solvent (S) in the presence of a Bronsted acid, and
the concentration of the silane condensate (A) is adjusted to 0.00005% by mass or more and 40% by mass or less by diluting the reaction liquid obtained by the hydrolyzation condensation with the organic solvent (S).
3 . The method for suppressing collapse of the three-dimensional structure according to claim 2 , wherein the surface treatment liquid comprises the Bronsted acid.
4 . The method for suppressing collapse of the three-dimensional structure according to claim 3 , wherein the Bronsted acid is an aliphatic carboxylic acid according.
5 . The method for suppressing collapse of the three-dimensional structure according to claim 1 , wherein a reaction rate represented by the following formula is 80% or more:
reaction rate (%)=(1−[α′]/[α])
wherein, in the formula, [α] is a concentration of the hydrolyzable silane compound at the start of reaction, and [α′] is a concentration of the unreacted hydrolyzable silane compound when measuring reaction rate.
6 . The method for suppressing collapse of the three-dimensional structure according to claim 1 , wherein, in the formula (A1-1), the R a1 is the alkyl group having 1 or more and 12 or less carbon atoms, and the R a2 is the alkoxy group having 1 or more and 4 or less carbon atoms.
7 . The method for suppressing collapse of the three-dimensional structure according to claim 1 , wherein the content of the trifunctional silane compound (A1) is 90% by mass or more with respect to a mass of the hydrolyzable silane compound.