Light-emitting device and manufacturing method thereof

A method for manufacturing a light-emitting device, comprising the steps of:

• forming a first gate electrode layer and a second gate electrode layer;
• forming a gate insulating layer over the first gate electrode layer and the second gate electrode layer;
• forming a first source and drain electrode layers over the gate insulating layer so as to overlap the first gate electrode layer;
• forming over the gate insulating layer, a first oxide semiconductor layer so as to overlap the first gate electrode layer, a part of the first source electrode layer, and a part of the first drain electrode layer, and a second oxide semiconductor layer so as to overlap the second gate electrode layer;
• forming an oxide insulating layer so as to be in contact with a part of the second oxide semiconductor layer and with a top surface and a side surface of the second oxide semiconductor layer;
• forming a second source and drain electrode layers over the second oxide semiconductor layer, and forming a connection electrode layer over the oxide insulating layer so as to be electrically connected to the first drain electrode layer;
• forming a color filter layer over the oxide insulating layer which overlaps the first oxide semiconductor layer;
• and
• forming over the color filter layer, a first electrode which is electrically connected to the connection electrode layer, a light-emitting layer, and a second electrode.