An etchant composition includes phosphoric acid and a silane compound represented by the following Chemical Formula 1:
wherein A is an n-valent radical, L is C
1
-C
5
hydrocarbylene, R
1
to R
3
are independently hydrogen, hydroxy, hydrocarbyl, or alkoxy, in which R
1
to R
3
exist respectively or are connected to each other by a heteroelement, and n is an integer of 2 to 5.