Array substrate and manufacturing method thereof and display device

A manufacturing method of an array substrate comprising steps of:

• S10, forming a pattern including a common electrode line and a gate of a thin film transistor on a base;
• S11, forming a gate insulation layer above the pattern including the common electrode line and the gate of the thin film transistor;
• S12, forming an active layer of the thin film transistor on the gate insulation layer above the gate;
• S13, forming an etch stop layer above the gate insulation layer and the active layer of the thin film transistor;
• S15, forming a passivation layer above the etch stop layer, wherein the manufacturing method further comprises steps of:
• S14, forming a main via, so that the main via is above the common electrode line and reaches the common electrode line;
• S16, forming a pattern including a main connection portion, so that the main connection portion is at least partially provided in the main via, the main connection portion comprises an upper main connection portion and a lower main connection portion, the lower main connection portion comprises a main body and a flange provided on the main body and extending towards a direction away from a center of the main via, a lower end of the upper main connection portion is connected to the flange, and the main body is connected to the common electrode line;
• and
• S17, forming a pattern of a common electrode, so that the common electrode is connected to an upper end of the upper main connection portion.