Display substrate, method of manufacturing display substrate, and display device including display substrate

A method of manufacturing a display substrate, the method comprising:

• forming a semiconductor member that overlaps a pixel area of a substrate;
• forming a gate electrode that overlaps the semiconductor member;
• forming a source electrode and a drain electrode that directly contact the semiconductor member;
• forming a pad electrode that overlaps a pad area of the substrate;
• forming an inorganic insulation layer that covers each of the source electrode, the drain electrode, and the pad electrode;
• forming an organic insulation member on the inorganic insulation layer, wherein the organic insulation member has a first positive maximum thickness in a direction perpendicular to the substrate at the pixel area of the substrate, has a second positive maximum thickness in the direction perpendicular to the substrate less than the first thickness at the pad area of the substrate, exposes a first portion of the inorganic insulation layer on the drain electrode, and exposes a second portion of the inorganic insulation layer on the pad electrode;
• removing the first portion of the inorganic insulation layer and the second portion of the inorganic insulation layer using an etching gas;
• and
• partially removing the organic insulation member to form a planarization layer.