Semiconductor device and display device including the semiconductor device

A semiconductor device comprising:

• a glass substrate;
• and
• a transistor comprising:
• a gate electrode comprising copper and titanium;
• a first insulating film over the gate electrode;
• an oxide semiconductor film comprising a region which overlaps with the gate electrode with the first insulating film therebetween;
• a source electrode electrically connected to the oxide semiconductor film;
• a drain electrode electrically connected to the oxide semiconductor film;
• and
• a second insulating film over the oxide semiconductor film, the source electrode, and the drain electrode,
• wherein the source electrode and the drain electrode each comprise a first conductive film, a second conductive film over and in contact with the first conductive film, and a third conductive film over and in contact with the second conductive film,
• wherein the second conductive film includes copper,
• wherein the first conductive film and the third conductive film include an oxide including at least one of In and Zn,
• wherein the oxide semiconductor film comprises indium, gallium, and zinc,
• wherein an end portion of the second conductive film comprises a region including copper and an element included in the second insulating film,
• wherein the first conductive film includes a region located outward from a portion of the end portion of the second conductive film,
• wherein each of the first conductive film and the third conductive film includes a region overlapping with the region of the end portion of the second conductive film, and
• wherein the region of the end portion of the second conductive film is in contact with a bottom surface of the third conductive film and a top surface of the first conductive film.

A semiconductor device comprising:

• a pixel portion;
• a terminal portion;
• a source-driver circuit;
• a plurality of gate-driver circuits;
• a sealant provided to surround the pixel portion and the plurality of gate-driver circuits;
• a liquid-crystal element;
• a glass substrate;
• and
• a channel-etched transistor in the pixel portion comprising:
• a gate electrode comprising copper and titanium;
• a first insulating film over the gate electrode;
• an oxide semiconductor film comprising a region which overlaps with the gate electrode with the first insulating film therebetween;
• a source electrode electrically connected to the oxide semiconductor film;
• a drain electrode electrically connected to the oxide semiconductor film;
• and
• a second insulating film over the oxide semiconductor film, the source electrode, and the drain electrode,
• wherein the source electrode and the drain electrode each comprise a first conductive film, a second conductive film over and in contact with the first conductive film, and a third conductive film over and in contact with the second conductive film,
• wherein the second conductive film includes copper,
• wherein the first conductive film and the third conductive film include an oxide including at least one of In and Zn,
• wherein the oxide semiconductor film comprises indium, gallium, and zinc,
• wherein an end portion of the second conductive film comprises a region including copper and another element,
• wherein each of the first conductive film and the third conductive film includes a region overlapping with the region of the end portion of the second conductive film, and
• wherein the region of the end portion of the second conductive film is in contact with a bottom surface of the third conductive film and a top surface of the first conductive film.