Patent ID: 7588881

Claim:
A method of making a thin film transistor liquid array substrate, comprising the steps of: providing a substrate with a double-layer film on a surface thereof, wherein the double-layer film includes a first transparent conductive layer on the surface of the substrate and a first metal layer on the first transparent conductive layer; performing a first photomask process, which includes the steps of using a gray-scale photomask to form a gate, a scan line and a bottom electrode of a storage capacitor, wherein the gate and the scan line are constructed by the first transparent conductive layer and the first metal layer, and the bottom electrode of the storage capacitor is constructed by the first transparent conductive layer; forming a gate insulating layer, a first semiconductor layer and a second semiconductor layer in sequence to cover the substrate, the gate, the scan line and the bottom electrode of the storage capacitor; exposing a bottom of the substrate under rays, wherein the patterned first metal layer is used to be a light shield to form a channel layer and an ohmic contact layer; forming a second metal layer to cover the gate insulating layer, the channel layer and the ohmic contact layer; performing a second photomask process to pattern the second metal layer in order to define a source/drain and a data line and break the ohmic contact layer between the source and the drain and expose the bottom electrode; forming a passivation layer to cover the substrate, the source/drain and the bottom electrode of the storage capacitor; performing a third photomask process to make at least a via on the passivation layer; forming a second transparent conductive layer to cover the passivation layer and cover the via to electrically connect the drain; and performing a fourth photomask process to pattern the second transparent conductive layer and form a pixel electrode.