Thin-Film Transistor Array Substrate and Organic Light-Emitting Display Device Including the Same

A manufacturing method for manufacturing an organic light emitting diode (OLED) display device, the manufacturing method comprising:

• forming a conducting layer on a substrate;
• forming a buffer insulating film on the conducting layer;
• forming an active layer of a transistor on the buffer insulating film;
• forming a gate insulating film on the buffer insulating film over the conducting layer and on the active layer of the transistor;
• forming a first connecting contact hole through the gate insulating film and the buffer insulating film to expose the conducting layer;
• forming a second connecting contact hole through the gate insulating film to expose the active layer of the transistor;
• forming a gate electrode on the gate insulating film over a channel region of the active layer of the transistor;
• and
• concurrently with forming the gate electrode, forming a first connecting pattern on the gate insulating film, the first connecting pattern connecting to the conducting layer via the first connecting contact hole, and the first connecting pattern connecting to the active layer of the transistor via the second connecting contact hole.