Patent ID: 7995183

Claim:
A semiconductor device comprising: a first substrate; a first thin film transistor formed over the first substrate; a pixel electrode electrically connected to said first thin film transistor; a first driver circuit formed over a second substrate, said first driver circuit comprising a second thin film transistor including a channel forming region comprising crystalline silicon, a terminal formed on a same layer as a source electrode of the second thin film transistor, an insulating film formed over the terminal where a portion of the terminal is exposed in an opening of the insulating film, a barrier metal layer formed over the insulating film and the terminal so that the barrier metal layer is in contact the portion of the terminal, and a bump formed on the barrier metal layer, wherein said second substrate is placed on one surface of said first substrate so that the bump is located between the first substrate and the second substrate; and a second driver circuit formed over a third substrate, said second driver circuit comprising a third thin film transistor including a channel forming region comprising crystalline silicon wherein said third substrate is placed on one surface of said first substrate, wherein a gate insulating film of the second thin film transistor is thicker than a gate insulating film of the third thin film transistor.