Patent ID: 7492418

Claim:
A liquid crystal display device, comprising: a substrate; a gate electrode over the substrate; a first semiconductor layer over the gate electrode; a second semiconductor layer over the first semiconductor layer defining a separation region with the first semiconductor layer; a first metal layer on the second semiconductor layer to define a separation region, wherein the first metal layer is patterned in a same pattern as the second semiconductor layer such that an outer edge of the first metal layer and an outer edge of the second semiconductor layer are lined up with one another to define a separation region for exposing some surfaces of the first semiconductor layer; source and drain electrodes, each having a first portion overlapping with the first metal layer and the second semiconductor layer to define a first upper portion of the separation region that abuts the lined up outer edges of the first and second semiconductor layers, and a second portion overlapping with the substrate around the gate electrode, wherein the source and drain electrodes include a second and a third metal layer, wherein the first, second and third metal layers comprise a same step shape that are symmetrical with respect to each other, the second metal layer extends beyond edges of the first semiconductor layer, the first metal layer extends only to edges of the first semiconductor layer, and the first and third metal layers do not contact each other; and a data pad over the substrate including the second and third metal layers.