Silicon nitride film etching composition and etching method using the same

A silicon nitride film etching composition comprising:

• a phosphoric acid, quaternary ammonium silicate, a silicon compound represented by the following Chemical Formula 1, and a residual amount of water:
• wherein
• R1 is C1-20 aminoalkyl and —CH2— of the alkyl may be replaced with —NR′— or —O— in which R′ is hydrogen, C1-7 alkyl, C1-7 hydroxyalkyl, or C1-7 aminoalkyl;
• R2 to R4 are independently of one another hydrogen, a halogen, amino, cyano, hydroxy, C1-20 alkoxy, C1-20 alkyl, C1-20 aminoalkyl, or
• in which R11 to R14 are independently of one another hydrogen, C1-20 alkyl, or C1-20 hydroxyalkyl;
• L1 is C1-20 alkylene and —CH2— of the alkylene may be replaced with —O—, —NR″—, or a combination thereof in which R″ is hydrogen or C1-7 alkyl;
• a is an integer selected from 0 to 10;
• and
• b is an integer selected from 1 to 3.