Disclosed is a TFT substrate, including a substrate and a gate electrode thereon. A gate insulation layer over the substrate covers the gate electrode. An active layer is disposed over the gate insulation layer. An etch stop layer is disposed over the active layer and the gate insulation layer. A first opening penetrates the etch stop layer to expose a first part of the active layer. A source electrode over the etch stop layer is electrically connected to the first part of the active layer through the first opening. A first inorganic insulation layer is disposed over the source electrode and the etch stop layer. A second opening penetrates the first inorganic insulation layer and the etch stop layer to expose a second part of the active layer.