Porous Separator for Secondary Battery and Manufacturing Method Thereof

Provided is a porous separator for a secondary battery including an inorganic oxide layer formed on a porous substrate by an atomic layer deposition process, such that a thin separator having excellent heat stability, permeability and electrolyte impregnability may be provided by controlling specific conditions in the process and thicknesses of the inorganic oxide layers on a surface and inside of the porous separator.