Method for manufacturing semiconductor device

A method for manufacturing a semiconductor device comprising:

• forming a gate electrode;
• forming a gate insulating layer over the gate electrode;
• forming a semiconductor layer comprising an oxide semiconductor including indium over the gate insulating layer;
• processing the semiconductor layer by wet etching to form an island-shaped semiconductor layer;
• forming a conductive layer over the island-shaped semiconductor layer;
• processing the conductive layer by first dry etching to form a first conductive layer and a second conductive layer;
• and
• processing the island-shaped semiconductor layer by second dry etching to form a recessed portion in the island-shaped semiconductor layer.

A method for manufacturing a semiconductor device comprising:

• forming a gate electrode;
• forming a gate insulating layer over the gate electrode;
• forming a semiconductor layer comprising an oxide semiconductor including indium over the gate insulating layer;
• processing the semiconductor layer by wet etching to form an island-shaped semiconductor layer;
• forming a conductive layer over the island-shaped semiconductor layer;
• processing the conductive layer by dry etching to form a first conductive layer and a second conductive layer;
• and
• processing the island-shaped semiconductor layer by the dry etching to form a recessed portion in the island-shaped semiconductor layer.

A method for manufacturing a semiconductor device comprising:

• forming a gate electrode;
• forming a gate insulating layer over the gate electrode;
• forming a semiconductor layer comprising an oxide semiconductor including indium over the gate insulating layer;
• processing the semiconductor layer by wet etching to form an island-shaped semiconductor layer, wherein the island-shaped semiconductor layer is overlapped with the gate electrode in such a manner that the island-shaped semiconductor layer does not extend beyond any side edge of the gate electrode;
• forming a conductive layer over the island-shaped semiconductor layer;
• and
• processing the conductive layer by dry etching to form a first conductive layer and a second conductive layer.

A method for manufacturing a semiconductor device comprising:

• forming a gate electrode;
• forming a gate insulating layer comprising a first oxide insulator over the gate electrode;
• forming a semiconductor layer comprising an oxide semiconductor including indium over the gate insulating layer;
• processing the semiconductor layer by wet etching to form an island-shaped semiconductor layer, wherein the island-shaped semiconductor layer is overlapped with the gate electrode in such a manner that the island-shaped semiconductor layer does not extend beyond any side edge of the gate electrode;
• forming a conductive layer over the island-shaped semiconductor layer;
• processing the conductive layer by dry etching to form a first conductive layer and a second conductive layer;
• forming a first insulating layer comprising a second oxide insulator over the semiconductor layer, the first conductive layer and the second conductive layer;
• forming a second insulating layer comprising a third oxide insulator over the first insulating layer;
• forming a third insulating layer comprising an organic insulator over the second insulating layer;
• and
• forming a pixel electrode over the third insulating layer so as to be electrically connected to one of the first conductive layer and the second conductive layer.