Organic light emitting display and manufacturing method of the same

A method for manufacturing an organic light emitting display device, comprising:

• forming a transistor on a substrate;
• forming a first insulation layer on the transistor;
• forming a metal shield layer on the first insulation layer, the metal shield layer directly on and physically contacting one of a source electrode and a drain electrode of the transistor;
• forming a second insulation layer on the metal shield layer;
• forming a cathode on the second insulation layer to be directly connected to the another one of the source electrode and the drain electrode of the transistor;
• after forming the cathode, forming a bank layer having an opening on the cathode;
• performing plasma pretreatment on the cathode to remove an oxide layer that is naturally formed on a surface of the cathode and to suppress an oxidation of the surface of the cathode;
• forming a metal buffer layer directly on and physically contacting the cathode at the opening of the bank layer to prevent the oxidation of the cathode and to improve electron injection efficiency;
• forming an organic light emitting layer directly on and contacting the metal buffer layer;
• and
• forming an anode on the organic light emitting layer,
• wherein a thickness of the metal buffer layer is approximately 1 Å to 50 Å,
• wherein in said performing plasma pretreatment, one of nitrogen plasma and argon plasma is used,
• wherein said performing plasma pretreatment and said forming the metal buffer are consecutively performed in an identical chamber.