Thin film transistor substrate and display device comprising the same

A thin film transistor substrate comprising a first thin film transistor and a second thin film transistor on a base substrate,

• wherein the first thin film transistor includes:
• a first active layer on the base substrate;
• a first conductive material layer on the first active layer;
• and
• a first gate electrode spaced apart from the first active layer and at least partially overlapping with the first active layer;
• a first source electrode in contact with an upper surface portion of the first conductive material layer;
• and
• a first drain electrode in contact with another upper surface portion of the first conductive material layer,
• wherein the second thin film transistor includes:
• a second active layer on the base substrate;
• a second conductive material layer on the second active layer;
• and
• a second gate electrode spaced apart from the second active layer and at least partially overlapping with the second active layer;
• a second source electrode in contact with an upper surface portion of the second conductive material layer;
• and
• a second drain electrode in contact with another upper surface portion of the second conductive material layer,
• wherein the first source electrode and the first drain electrode are formed of a different material than the first conductive material layer;
• wherein the second source electrode and the second drain electrode are formed of a different material than the second conductive material layer;
• wherein the first active layer being is disposed between the base substrate and the second active layer,
• wherein the second active layer beings is disposed between the first active layer and the second gate electrode,
• wherein the first gate electrode being is disposed on the same layer as the second active layer,
• wherein the first active layer includes:
• a first channel portion;
• a first source connection portion connected to one side of the first channel portion;
• a first drain connection portion connected to the other side of the first channel portion, and
• the first conductive material layer is disposed on the first source connection portion and the first drain connection portion, and is not disposed on the first channel portion,
• wherein the second active layer includes:
• a second channel portion;
• a second source connection portion connected to one side of the second channel portion;
• a second drain connection portion connected to the other side of the second channel portion, and
• the second conductive material layer is disposed on the second source connection portion and the second drain connection portion and is not disposed on the second channel portion, and
• wherein each of the second source connection portion and the second drain connection portion is disposed between the first active layer and the second conductive material layer.