Etchant composition and manufacturing method of display device using the same

A manufacturing method of a display device, comprising:

• forming a metal layer including copper on a substrate;
• forming a transistor on the metal layer;
• and
• etching the metal layer with an etchant composition, wherein
• the etchant composition includes:
• about 5.0 to about 20.0 wt % of a persulfate;
• about 0.01 to about 15.0 wt % of a sulfonic acid;
• about 0.01 to about 2.0 wt % of a fluorine compound;
• about 0.01 to about 5.0 wt % of a 4-nitrogen cyclic compound;
• about 0.01 to about 1.0 wt % of an amino acid including a hydrophobic group having at least two carbon atoms;
• and
• water, and
• a weight ratio of the amino acid to the 4-nitrogen cyclic compound is in a range of about 1:16 to about 1:60.