Method for manufacturing bottom-gate TFT (Thin Film Transistor) substrate

The invention provides a method for manufacturing a bottom-gate TFT (Thin Film Transistor) substrate, which comprises the steps of forming a first etching barrier layer on a gate metal layer, and forming a second etching barrier layer on a source-drain metal layer; when via holes are formed respectively above the gate metal layer and the source-drain metal layer, firstly etching to the first etching barrier layer and the second etching barrier layer by adopting a first etching gas, forming a first primary via hole and a second primary via hole respectively above the gate metal layer and the source-drain metal layer correspondingly, then etching the first etching barrier layer below the first primary via hole and the second etching barrier layer below the second primary via hole simultaneously by adopting a second etching gas, wherein the first etching barrier layer and the second etching barrier layer can be etched through simultaneously because the first etching barrier layer and the second etching barrier l