A method is for hydrophobization of a surface of a silicon-containing film by atomic layer deposition (ALD), wherein the surface is subjected to atmospheric exposure. The method includes: (i) providing a substrate with a silicon-containing film formed thereon; and (ii) forming on a surface of the silicon-containing film a hydrophobic atomic layer as a protective layer subjected to atmospheric exposure, by exposing the surface to a silicon-containing treating gas without exciting the gas. The treating gas is capable of being chemisorbed on the surface to form a hydrophobic atomic layer thereon.