Samsung Display Co., Ltd.

Dongwoo Fine-chem Co., Ltd.

Aeg Co., Ltd.

Hyeonsu Cho

Shinhyuk Yang

Jeehoon Kim

Beomsoo Kim

Donghan Kang

Youngjin Yoon

Eunwon Lee

Yujin Kim

Jongmoo Huh

Jihun Park

An etchant including: persulfate; a fluorine-containing compound; a chlorine-containing compound; a cyclic amine compound; an inorganic acid; a first compound; and water, wherein the first compound is a compound containing: a sulfonic group, a sulfonic acid group, or a combination thereof; and an amine group, and an interfacial permeation inhibition index (Y) of the etchant is a value of at least about 0.10 and not more than about 0.35, the interfacial permeation inhibition index (Y) being a value calculated by Equation 1. The description of Equation 1 is as in the specification.

Etchant

An etchant including: persulfate; a fluorine-containing compound; a chlorine-containing compound; a cyclic amine compound; an inorganic acid; sulfate; and water, wherein a tip control index (Y) of the etchant is a value of at least about 45.0 and not more than about 70.0, the tip control index (Y) being a value calculated by Equation 1:=1.0×10(1)+1.0×10(2)+5.0×10(3)+1.5×(1)×(2)+2.0×10(1)×(3)+2.0×10(2)×(3)  Equation 1The description of Equation 1 is as in the specification.

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Iksan-si, South Korea

Hyeonsu Cho